gallium/util: minor clean-ups in u_framebuffer.c

Replace tabs w/ spaces, move vars.

Signed-off-by: Brian Paul <brian.paul@broadcom.com>
Reviewed-by: Neha Bhende <neha.bhende@broadcom.com>
Reviewed-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/35238>
1 file changed