drm/ttm: Use a static string instead of an array of char *

Make the object a bit smaller by using a simple string instead
of a format string and array of char *.

$ size drivers/gpu/drm/ttm/ttm_page_alloc_dma.o*
   text	   data	    bss	    dec	    hex	filename
   8820	    216	   4136	  13172	   3374	drivers/gpu/drm/ttm/ttm_page_alloc_dma.o.defconfig.new
   8910	    216	   4136	  13262	   33ce	drivers/gpu/drm/ttm/ttm_page_alloc_dma.o.defconfig.old
  25383	   5044	   4384	  34811	   87fb	drivers/gpu/drm/ttm/ttm_page_alloc_dma.o.allyesconfig.new
  25797	   5428	   4384	  35609	   8b19	drivers/gpu/drm/ttm/ttm_page_alloc_dma.o.allyesconfig.old

Miscellanea:

o The h array had more entries than were emitted, all are now removed

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>