mplayer2: drop FULL_OPTIMIZATION_armv7a and add -fno-tree-vectorize

* we had -ftree-vectorize instead of -frename-registers here, but that's
  causing ICE with latest gcc-4.6 from meta-oe
* qemux86-64 was still failing without -fno-tree-vectorize
* similar to issue in libvpx
  http://lists.linuxtogo.org/pipermail/openembedded-devel/2011-November/036001.html
  and lowering to -O3 is not enough in this case
  | libmpcodecs/ad_imaadpcm.c: In function 'qt_ima_adpcm_decode_block':
  | libmpcodecs/ad_imaadpcm.c:177:12: internal compiler error: Segmentation fault
  | Please submit a full bug report,
  | with preprocessed source if appropriate.
  | See <http://gcc.gnu.org/bugs.html

> for instructions.
  | make: *** [libmpcodecs/ad_imaadpcm.o] Error 1

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>