drm/qxl: remove qxl_log_level global

Smatch reports this issue
qxl_kms.c:36:5: warning: symbol 'qxl_log_level' was not declared. Should it be static?

qxl_log_level is defined qxl_kms.c but unused, so remove.
Signed-off-by: Tom Rix <trix@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220421142054.3751507-1-trix@redhat.comSigned-off-by: Gerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/qxl/qxl_kms.c

@@ -33,8 +33,6 @@
 #include "qxl_drv.h"
 #include "qxl_object.h"
 
-int qxl_log_level;
-
 static bool qxl_check_device(struct qxl_device *qdev)
 {
 	struct qxl_rom *rom = qdev->rom;