drm/crc-debugfs: Also sprinkle irqrestore over early exits

I. was. blind.

Caught with vkms, which has some really slow crc computation function.

Fixes: 1882018a70e0 ("drm/crc-debugfs: User irqsafe spinlock in drm_crtc_add_crc_entry")
Cc: Rodrigo Siqueira <[e-mail]>
Cc: Tomeu Vizoso <[e-mail]>
Cc: Emil Velikov <[e-mail]>
Cc: Benjamin Gaignard <[e-mail]>
Cc: Ville Syrjälä <[e-mail]>
Reviewed-by: Emil Velikov <[e-mail]>
Reviewed-by: Benjamin Gaignard <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/drm_debugfs_crc.c

···
 
 	/* Caller may not have noticed yet that userspace has stopped reading */
 	if (!crc->entries) {
-		spin_unlock(&crc->lock);
+		spin_unlock_irqrestore(&crc->lock, flags);
 		return -EINVAL;
 	}
 
···
 		bool was_overflow = crc->overflow;
 
 		crc->overflow = true;
-		spin_unlock(&crc->lock);
+		spin_unlock_irqrestore(&crc->lock, flags);
 
 		if (!was_overflow)
 			DRM_ERROR("Overflow of CRC buffer, userspace reads too slow.\n");