sunxi: Stop differentiating between 512M and 1G variants of the same board

sunxi: Stop differentiating between 512M and 1G variants of the same board

While working on adding more boards I noticed that we lack a config for
the 512M cubieboard, and that some of the new boards which I want to add also
have 512M and 1G variants, rather then adding 2 defconfig's for all of these,
lets switch the exising boards which have both a 512M and 1024M variant over
to the sun4i dram autoconfig code.

This also drops the foo_RAMSIZE_defconfig variants of boards where we currently
have 2 separate configs already.

Note:
1) The newly introduced CONFIG_DRAM_EMR1 kconfig value is not used with
a value other then its default for now, but we need this to be configurable
to support some new boards with auto dram config.

2) We always set all CONFIG_DRAM_foo values in defconfigs, even if they match
the defaults, this is done to make it more clear what values are used for a
certain board.

This has been tested on a Mele A1000, Mini-X and a Cubieboard, all 1G
variants, the dram autoconfig code has also been tested on a 512M mk802
(a defconfig for the mk802 is added in a later patch).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>