drm/amdgpu: Prefer #if IS_ENABLED over #if defined in amdgpu_drv.c

Adhere to linux coding style

Fixes the following:

WARNING: Prefer IS_ENABLED(<FOO>) to CONFIG_<FOO> || CONFIG_<FOO>_MODULE
+#if defined(CONFIG_DRM_RADEON) || defined(CONFIG_DRM_RADEON_MODULE)

WARNING: Prefer IS_ENABLED(<FOO>) to CONFIG_<FOO> || CONFIG_<FOO>_MODULE
+#if defined(CONFIG_DRM_RADEON) || defined(CONFIG_DRM_RADEON_MODULE)

Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -584,7 +584,7 @@ module_param_named(timeout_period, amdgpu_watchdog_timer.period, uint, 0644);
  */
 #ifdef CONFIG_DRM_AMDGPU_SI
 
-#if defined(CONFIG_DRM_RADEON) || defined(CONFIG_DRM_RADEON_MODULE)
+#if IS_ENABLED(CONFIG_DRM_RADEON) || IS_ENABLED(CONFIG_DRM_RADEON_MODULE)
 int amdgpu_si_support = 0;
 MODULE_PARM_DESC(si_support, "SI support (1 = enabled, 0 = disabled (default))");
 #else
@@ -603,7 +603,7 @@ module_param_named(si_support, amdgpu_si_support, int, 0444);
  */
 #ifdef CONFIG_DRM_AMDGPU_CIK
 
-#if defined(CONFIG_DRM_RADEON) || defined(CONFIG_DRM_RADEON_MODULE)
+#if IS_ENABLED(CONFIG_DRM_RADEON) || IS_ENABLED(CONFIG_DRM_RADEON_MODULE)
 int amdgpu_cik_support = 0;
 MODULE_PARM_DESC(cik_support, "CIK support (1 = enabled, 0 = disabled (default))");
 #else