Add __clear_cache to libcompiler_rt-extras.a for MIPS

libgcc has an empty implementation for MIPS architectures.
This fixes ART codegen_test on CI20 board.

(cherry picked from commit 033e09b8364f38607c379669564bbef028d185a8)

Change-Id: Ia2b846708695ce3ad9bf2aeca59441d1f2676904
1 file changed