Revert assembler build flags setting
Revert assembler build flags setting

This change reverts previous change for setting up assembler flags

Change-Id: Ied74bc2b7afe5661aea3a6a7e9984388b25bfd1c
Signed-off-by: Michal Widera <5b4a5292a5effd3db6c0a8779b28dbc024e02a7f@arm.com>

ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build,ARM-software/bob-build