drm/i915: Remove unused intel_gmbus_set_speed() function

The intel_gmbus_set_speed() function is not used anywhere, remove it.

Note drivers/gpu/drm/gma500 has its own copy called
gma_intel_gmbus_set_speed() which is used, the intel_gmbus_set_speed()
version in the i915 code is not used at all
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211121191001.252076-1-hdegoede@redhat.com

drivers/gpu/drm/i915/display/intel_gmbus.c

@@ -931,13 +931,6 @@ struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
 	return &dev_priv->gmbus[pin].adapter;
 }
 
-void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
-{
-	struct intel_gmbus *bus = to_intel_gmbus(adapter);
-
-	bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
-}
-
 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
 {
 	struct intel_gmbus *bus = to_intel_gmbus(adapter);

drivers/gpu/drm/i915/display/intel_gmbus.h

@@ -41,7 +41,6 @@ int intel_gmbus_output_aksv(struct i2c_adapter *adapter);
 
 struct i2c_adapter *
 intel_gmbus_get_adapter(struct drm_i915_private *dev_priv, unsigned int pin);
-void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed);
 void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit);
 bool intel_gmbus_is_forced_bit(struct i2c_adapter *adapter);
 void intel_gmbus_reset(struct drm_i915_private *dev_priv);