Override the hal pixel format for samsung codecs
Remove an unnecessary check
Only try to load the IOMX specific functions in IOMX builds
Remove some USE_IOMX ifdefs

The fewer ifdefs we need, the clearer the code is. (We get fewer
warnings about unused variables this way as well.)
Get rid of some more ifdefs
cosmetic: remove debugs, stray leftovers, and reindent