MIPS DSP composition functions optimizations.

MIPS DSP composition functions optimizations.

List of optimized routines:
- comp_func_DestinationOver
- comp_func_SourceIn
- comp_func_DestinationIn
- comp_func_DestinationOut
- comp_func_SourceAtop
- comp_func_DestinationAtop
- comp_func_XOR
- comp_func_SourceOut
- comp_func_solid_SourceOver
- comp_func_solid_DestinationOver
- comp_func_solid_SourceIn
- comp_func_solid_DestinationIn
- comp_func_solid_SourceAtop
- comp_func_solid_DestinationAtop
- copm_func_solid_XOR
- comp_func_solid_SourceOut

Previously optimized routines qt_blend_argb32_on_argb32_mips_dsp and
comp_func_Source_mips_dsp are redesigned and rewritten.

Overall improvement by running tst_bench_blendbench benchmark app
from tests/benchmarks/gui/image/blendbench/ is 27%.

Change-Id: I6ab09b17cac10f4aded59787074ab4c89e72ccac
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>