drm/nouveau/fifo/gv100-: set gv100_fifo_runlist storage-class to static

sparse reports
drivers/gpu/drm/nouveau/nvkm/engine/fifo/gv100.c:56:1: warning: symbol 'gv100_fifo_runlist' was not declared. Should it be static?

gv100_fifo_runlist is only used in gv100.c, so change it to static.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220528141836.4155970-1-trix@redhat.com