drm/radeon: change cik_default_state table from global to static

Sparse reports these issues
cik_blit_shaders.c:31:11: warning: symbol 'cik_default_state' was not declared. Should it be static?
cik_blit_shaders.c:246:11: warning: symbol 'cik_default_size' was not declared. Should it be static?

cik_default_state and cik_default_size are only used in cik.c. Single file symbols
should be static. So move their definitions to cik_blit_shaders.h and change their
storage-class-specifier to static.

Remove unneeded cik_blit_shader.c

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>