build: suppress git apply warning for whitespace in patches

Add a git apply option to suppress space before tab in indent warnings
when applying patches. Those warnings are triggered by dpdk code format.

Signed-off-by: Liangxing Wang <liangxing.wang@arm.com>
Reviewed-by: Nathan Brown <nathan.brown@arm.com>
Change-Id: I5c3e979a4c2cdb23d6e8f4f759c40f7bcef4ae11