gallium/dri2: Move image->texture assignment after image NULL check.

Fix defect reported by Coverity Scan.

Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking image suggests that it may be
null, but it has already been dereferenced on all paths leading to
the check.

Fixes: ad609bf55a87 ("frontend/dri: Implement mapping individual planes.")
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6807>
1 file changed