Remove (hopefully) unnecessary BoringSSL build flag.

At one point, due to some missing features in clang assembler,
BoringSSL's required the consumer pass a particular -march line to some
ARM assembly files. Since then, clang assembler added the missing
features and BoringSSL switched to setting the target internally. This
should no longer be necessary in Android build files. (If I'm wrong, the
failure mode would be a build failure.)

Test: mma
Change-Id: I98adccca3338339882649503a17cbce9b2385219
1 file changed