drm/radeon: remove set but not used variable 'radeon_connector'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/gpu/drm/radeon/radeon_display.c: In function radeon_crtc_scaling_mode_fixup:
drivers/gpu/drm/radeon/radeon_display.c:1685:27: warning: variable radeon_connector set but not used [-Wunused-but-set-variable]

It is not used since commit 377bd8a98d7d ("drm/radeon:
use a fetch function to get the edid")

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: zhengbin <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/radeon/radeon_display.c

···
 	struct radeon_crtc *radeon_crtc = to_radeon_crtc(crtc);
 	struct radeon_encoder *radeon_encoder;
 	struct drm_connector *connector;
-	struct radeon_connector *radeon_connector;
 	bool first = true;
 	u32 src_v = 1, dst_v = 1;
 	u32 src_h = 1, dst_h = 1;
···
 			continue;
 		radeon_encoder = to_radeon_encoder(encoder);
 		connector = radeon_get_connector_for_encoder(encoder);
-		radeon_connector = to_radeon_connector(connector);
 
 		if (first) {
 			/* set scaling */