Convert all ARM assembler directives to lower case for clang's assembler.

This conversion was done by a script to convert .MACRO, .IFEQS, .ELSE,
.ENDIF, .ENDM, and .END to lowercase.

BUG=
R=andrew@webrtc.org, thakis@chromium.org

Review URL: https://webrtc-codereview.appspot.com/13059004

git-svn-id: http://webrtc.googlecode.com/svn/deps/third_party/openmax@6777 4adac7df-926f-26a2-2b94-8c16560cd09d