Just like _cogl_texture_2d_new_with_size(),
_cogl_texture_2d_new_from_bitmap() needs to check if an unsliced
texture can be created at the given size, or if hardware
limitations prevent this.
http://bugzilla.openedhand.com/show_bug.cgi?id=2014
Signed-off-by: Neil Roberts <neil@linux.intel.com>