arm: makefile: use -mcpu=cortex-a15 when targeting MSM Krait CPUs

Enable compiler optimizations specific to the Cortex-A15
processor when targeting MSM Krait CPUs. This is necessary
take advantage of the UDIV/SDIV instructions supported by
these processors. To accomplish this, we need to remove the
-march=armv7-a ISA restriction from the compiler options
because 'cortex-a15' is a superset of 'armv7-a'.

Change-Id: I6215aecc11fb4f77c971de7b84f68649ef234357
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
Makefile: restructre flag handling, also fix superset handling of a15 and armv7

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
vfp: hardfloat

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
drivers/mfd/wcd9xxx-irq: fix: warning: array subscript is above array bounds

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
Makefile: unaligned access, should be default anyway

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>