drm/nouveau/bios: make const arrays hwsq_signature and edid_sig static

Don't populate arrays hwsq_signature and edid_sig on the stack but
instead make them static. Makes the object code smaller by over 190
bytes:

Before:
   text    data     bss     dec     hex filename
  35676    3312      64   39052    988c nouveau_bios.o

After:
   text    data     bss     dec     hex filename
  35319    3472      64   38855    97c7 nouveau_bios.o

(gcc version 7.2.0 x86_64)
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_bios.c

@@ -1968,7 +1968,7 @@ static int load_nv17_hw_sequencer_ucode(struct drm_device *dev,
 	 * The microcode entries are found by the "HWSQ" signature.
 	 */
 
-	const uint8_t hwsq_signature[] = { 'H', 'W', 'S', 'Q' };
+	static const uint8_t hwsq_signature[] = { 'H', 'W', 'S', 'Q' };
 	const int sz = sizeof(hwsq_signature);
 	int hwsq_offset;
 
@@ -1984,7 +1984,7 @@ uint8_t *nouveau_bios_embedded_edid(struct drm_device *dev)
 {
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct nvbios *bios = &drm->vbios;
-	const uint8_t edid_sig[] = {
+	static const uint8_t edid_sig[] = {
 			0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 };
 	uint16_t offset = 0;
 	uint16_t newoffset;