Refactor audio_processing/aecm: Removed usage of macro WEBRTC_SPL_MUL_16_16_RSFT

The macro is defined as
#define WEBRTC_SPL_MUL_16_16_RSFT(a, b, c) \
(WEBRTC_SPL_MUL_16_16(a, b) >> (c))

where the latter macro is in C defined as
#define WEBRTC_SPL_MUL_16_16(a, b) \
((int32_t) (((int16_t)(a)) * ((int16_t)(b))))
(For definitions on ARMv7 and MIPS, see common_audio/signal_processing/include/spl_inl_{armv7,mips}.h)

The replacement consists of
- avoiding casts to int16_t if inputs already are int16_t
- adding explicit cast to <type> if result is assigned to <type> (other than int or int32_t)
- minor cleanups like remove of unnecessary parentheses and style changes

In addition an implicit cast from int32_t to int16_t was removed, which was a bug.

BUG=3348,3353
TESTED=Locally on Mac and trybots
R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/41169004

Cr-Commit-Position: refs/heads/master@{#8665}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8665 4adac7df-926f-26a2-2b94-8c16560cd09d
2 files changed