Remove SLP vectorization workaround.

This workaround is not needed any more.

Bug: 21301588
Change-Id: I84c1062f30ea3c83fed53dbc47b9bf83b1451e54
diff --git a/Android.mk b/Android.mk
index c010bd1..c8c0df7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -26,10 +26,6 @@
 
 my_cflags_arm64 := -DPNG_ARM_NEON_OPT=2
 
-# BUG: http://llvm.org/PR19472 - SLP vectorization (on ARM at least) crashes
-# when we can't lower a vectorized bswap.
-my_cflags_arm += -fno-slp-vectorize
-
 my_src_files_arm := \
 			arm/arm_init.c \
 			arm/filter_neon.S \