compat: backport devm_regmap_init()

compat: backport devm_regmap_init()

Backport devm_regmap_init() for I2C and SPI.
Asynchronous I/O support was added as of 3.9 and
since the regmap is part the core we don't want
to deal with trying a full backport replacement
yet. Given that no one as of next-20130328 uses
regmap asynchronous we simply warn if its ever
used for now. The regmap callbacks were made
bus agnostic as of commit 0135bbcc added on on
3.5 and becuase of this we we just remove all
that from our port given that we do this port
for kernels < 3.4.

This works with the old core regmap implementation
added as of 3.1 given that static inlines were
used as wrapper for calls and the bus context
was only used by the internal code.

mcgrof@frijol ~/linux-stable (git::master)$ git describe --contains c0eb4676
v3.4-rc1~126^2~4^2

mcgrof@frijol ~/linux-stable (git::master)$ git describe --contains 0d509f2b
v3.9-rc2~19^2~6^2~5

mcgrof@frijol ~/linux-stable (git::master)$ git describe --contains 0135bbcc
v3.5-rc1~117^2~7^3~6

commit c0eb46766d395da8d62148bda2e59bad5e6ee2f2
Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
Date:   Mon Jan 30 19:56:52 2012 +0000

    regmap: Implement managed regmap_init()

    Save error handling and unwinding code in drivers by providing managed
    versions of the regmap init functions, simplifying usage.

    Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
commit 0d509f2b112b21411712f0bf789b372987967e49
Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
Date:   Sun Jan 27 22:07:38 2013 +0800

    regmap: Add asynchronous I/O support

    Some use cases like firmware download can transfer a lot of data in quick
    succession. With high speed buses these use cases can benefit from having
    multiple transfers scheduled at once since this allows the bus to minimise
    the delay between transfers.

    Support this by adding regmap_raw_write_async(), allowing raw transfers to
    be scheduled, and regmap_async_complete() to wait for them to finish.

    Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
commit 0135bbcc7a0cc056f0203ff839466236b8e3dc19
Author: Stephen Warren <swarren@nvidia.com>
Date:   Wed Apr 4 15:48:30 2012 -0600

    regmap: introduce explicit bus_context for bus callbacks

    The only context needed by I2C and SPI bus definitions is the device
    itself; this can be converted to an i2c_client or spi_device in order
    to perform IO on the device. However, other bus types may need more
    context in order to perform IO. Enable this by having regmap_init accept
    a bus_context parameter, and pass this to all bus callbacks. The
    existing callbacks simply pass the struct device here. Future bus types
    may pass something else.

    Signed-off-by: Stephen Warren <swarren@nvidia.com>
    Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>