base: remove execute bit from utf8.h

I originally accidentally created this file with the execute bit on.

Test: mma

Change-Id: I8075ffdbb114475434ad48912a9dd24f19a9025b
Signed-off-by: Spencer Low <CompareAndSwap@gmail.com>
diff --git a/include/android-base/utf8.h b/include/android-base/utf8.h
old mode 100755
new mode 100644