Build - Disable -mcpu=cortex-a15 flag for krait

Disable -mcpu=cortex-a15 flag for krait.
Make it same as that of KK and use -march=armv7-a.

Change-Id: I76eaf87b84bdec5aa2dfbeec94a40289c095b13f
Signed-off-by: STELIX <ssspinni@gmail.com>