Fix conversion of 24bpp bitmaps to 32bpp fb when
CLRCONV_INVERT and/or CLRCONV_ALPHA is set.
* include/freerdp/codec/color.h (RGB32_to_BGR32): New inline function.
* libfreerdp/codec/color.c:
(freerdp_image_convert_24bpp): Fix CLRCONV_ALPHA and CLRCONV_INVERT
processing for 32bpp destination.
Unroll the conversion loop to process four pixels in one go using
32-bit load and store operations.