Remove GCC parameter "-march=native" for ARM

Summary:
Most popular versions of GCC can't identify platform on ARM if "-march=native" is specified. Remove it to unblock most people.
Closes https://github.com/facebook/rocksdb/pull/3346

Differential Revision: D6690544

Pulled By: siying

fbshipit-source-id: bbaba9fe2645b6b37144b36ea75beeff88992b49

build_tools/build_detect_platform

@@ -481,6 +481,9 @@ if test -z "$PORTABLE"; then
     COMMON_FLAGS="$COMMON_FLAGS -mcpu=$POWER -mtune=$POWER "
   elif test -n "`echo $TARGET_ARCHITECTURE | grep ^s390x`"; then
     COMMON_FLAGS="$COMMON_FLAGS -march=z10 "
+  elif test -n "`echo $TARGET_ARCHITECTURE | grep ^arm`"; then
+    # TODO: Handle this with approprite options.
+    COMMON_FLAGS="$COMMON_FLAGS"
   elif [ "$TARGET_OS" != AIX ] && [ "$TARGET_OS" != SunOS ]; then
     COMMON_FLAGS="$COMMON_FLAGS -march=native "
   elif test "$USE_SSE"; then