compat-wireless: driver-select: refactor select_drivers and eliminate redundant selec...

compat-wireless: driver-select: refactor select_drivers and eliminate redundant select_driver

These two functions are functionally identical when passed one argument,
and we'd also like to have the ability to modify Makefiles other than
drivers/net/wireless/Makefile the same way.  Introduce a
select_drivers_from_makefile which takes a Makefile argument, and
implement select_drivers using it.  Convert existing users of
select_driver to select_drivers, and remove the redundant function.

Signed-off-by: Steven Luo <steven@steven676.net>
Signed-off-by: Luis R. Rodriguez <mcgrof@frijolero.org>