drm/msm: make a5xx_show and a5xx_gpu_state_put static

The a5xx_show and a5xx_gpu_state_put objects are not exported
outside of the file, so make them static to avoid the following
warnings from sparse:

drivers/gpu/drm/msm/adreno/a5xx_gpu.c:1292:5: warning: symbol 'a5xx_gpu_state_put' was not declared. Should it be static?
drivers/gpu/drm/msm/adreno/a5xx_gpu.c:1302:6: warning: symbol 'a5xx_show' was not declared. Should it be static?

Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191009114607.701-1-ben.dooks@codethink.co.uk