drm/amd/pm/powerplay/hwmgr/smu7_hwmgr: Fix formatting and spelling issues

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:242: warning: Function parameter or member 'hwmgr' not described in 'smu7_enable_smc_voltage_controller'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4508: warning: Function parameter or member 'us_max_fan_rpm' not described in 'smu7_set_max_fan_rpm_output'
 drivers/gpu/drm/amd/amdgpu/../pm/powerplay/hwmgr/smu7_hwmgr.c:4508: warning: Excess function parameter 'usMaxFanRpm' description in 'smu7_set_max_fan_rpm_output'

Cc: Evan Quan <evan.quan@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c

@@ -235,7 +235,7 @@ static int smu7_get_current_pcie_lane_number(struct pp_hwmgr *hwmgr)
 /**
  * smu7_enable_smc_voltage_controller - Enable voltage control
  *
- * @hwmgr  the address of the powerplay hardware manager.
+ * @hwmgr:  the address of the powerplay hardware manager.
  * Return:   always PP_Result_OK
  */
 static int smu7_enable_smc_voltage_controller(struct pp_hwmgr *hwmgr)
@@ -4501,7 +4501,7 @@ static int smu7_display_configuration_changed_task(struct pp_hwmgr *hwmgr)
  * smu7_set_max_fan_rpm_output - Set maximum target operating fan output RPM
  *
  * @hwmgr:  the address of the powerplay hardware manager.
- * @usMaxFanRpm:  max operating fan RPM value.
+ * @us_max_fan_rpm:  max operating fan RPM value.
  * Return:   The response that came from the SMC.
  */
 static int smu7_set_max_fan_rpm_output(struct pp_hwmgr *hwmgr, uint16_t us_max_fan_rpm)