drm/amdgpu: new macro for determining 2ND_USB20PORT support

Used for determining 2ND_USB20PORT support from firmware_capability.
Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/include/atomfirmware.h

@@ -499,6 +499,7 @@ enum atombios_firmware_capability
 	ATOM_FIRMWARE_CAP_HWEMU_UMC_CFG = 0x00000100,
 	ATOM_FIRMWARE_CAP_SRAM_ECC      = 0x00000200,
 	ATOM_FIRMWARE_CAP_ENABLE_2STAGE_BIST_TRAINING  = 0x00000400,
+	ATOM_FIRMWARE_CAP_ENABLE_2ND_USB20PORT = 0x0008000,
 };
 
 enum atom_cooling_solution_id{