meta: Silence several 'unused parameter' warnings

meta: Silence several 'unused parameter' warnings

Silences many GCC warnings of the form:

drivers/common/meta.c: In function 'cleanup_temp_texture':
drivers/common/meta.c:1208:41: warning: unused parameter 'ctx' [-Wunused-parameter]
drivers/common/meta.c: In function 'setup_ff_blit_framebuffer':
drivers/common/meta.c:1453:46: warning: unused parameter 'ctx' [-Wunused-parameter]
drivers/common/meta.c: In function 'meta_glsl_blit_cleanup':
drivers/common/meta.c:1998:43: warning: unused parameter 'ctx' [-Wunused-parameter]
drivers/common/meta.c: In function 'meta_glsl_clear_cleanup':
drivers/common/meta.c:2287:44: warning: unused parameter 'ctx' [-Wunused-parameter]
drivers/common/meta.c: In function 'setup_ff_generate_mipmap':
drivers/common/meta.c:3365:45: warning: unused parameter 'ctx' [-Wunused-parameter]
drivers/common/meta.c: In function 'meta_glsl_generate_mipmap_cleanup':
drivers/common/meta.c:3556:54: warning: unused parameter 'ctx' [-Wunused-parameter]

There are a couple other similar warnings, but they are less trivial.  I
want to investigate these further before axing them.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Brian Paul <brianp@vmware.com>