gbm: Move getters to match order in header file (trivial)
gbm: Move getters to match order in header file (trivial)

Other things are out of order, but I need to add a getter so I'm just
fixing those.

This helps people adding to GBM know where the right place to put things
is.

Signed-off-by: Ben Widawsky <73675debcd8a436be48ec22211dcf44fe0df0a64@bwidawsk.net>
Reviewed-by: Eric Engestrom <de0b63cf2dfb1fae8ed3c3b4244856a05677d4f0@imgtec.com>
Acked-by: Daniel Stone <62e7e355d5d8400fa8384448796af0bf6be4ffae@collabora.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler