drm/radeon/radeon_i2c: Remove unused function

Remove the function radeon_best_encoder() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.
Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_i2c.c

@@ -1048,11 +1048,6 @@ struct radeon_i2c_chan *radeon_i2c_lookup(struct radeon_device *rdev,
 	return NULL;
 }
 
-struct drm_encoder *radeon_best_encoder(struct drm_connector *connector)
-{
-	return NULL;
-}
-
 void radeon_i2c_get_byte(struct radeon_i2c_chan *i2c_bus,
 			 u8 slave_addr,
 			 u8 addr,

drivers/gpu/drm/radeon/radeon_mode.h

@@ -745,8 +745,6 @@ extern void radeon_router_select_ddc_port(struct radeon_connector *radeon_connec
 extern void radeon_router_select_cd_port(struct radeon_connector *radeon_connector);
 extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector, bool use_aux);
 
-extern struct drm_encoder *radeon_best_encoder(struct drm_connector *connector);
-
 extern bool radeon_atombios_get_ppll_ss_info(struct radeon_device *rdev,
 					     struct radeon_atom_ss *ss,
 					     int id);