MAINTAINERS: fix up entry for AMD Powerplay

Fix the path to cover both the older powerplay infrastructure
and the newer SwSMU infrastructure.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

MAINTAINERS

@@ -977,12 +977,12 @@ L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
 F:	drivers/platform/x86/amd-pmc.*
 
-AMD POWERPLAY
+AMD POWERPLAY AND SWSMU
 M:	Evan Quan <evan.quan@amd.com>
 L:	amd-gfx@lists.freedesktop.org
 S:	Supported
 T:	git https://gitlab.freedesktop.org/agd5f/linux.git
-F:	drivers/gpu/drm/amd/pm/powerplay/
+F:	drivers/gpu/drm/amd/pm/
 
 AMD PTDMA DRIVER
 M:	Sanjay R Mehta <sanju.mehta@amd.com>