drm/radeon/si: add some missing regs to the VM reg checker

This register is needed for streamout to work properly.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

drivers/gpu/drm/radeon/si.c

@@ -2474,6 +2474,7 @@ static bool si_vm_reg_valid(u32 reg)
 	/* check config regs */
 	switch (reg) {
 	case GRBM_GFX_INDEX:
+	case CP_STRMOUT_CNTL:
 	case VGT_VTX_VECT_EJECT_REG:
 	case VGT_CACHE_INVALIDATION:
 	case VGT_ESGS_RING_SIZE:

drivers/gpu/drm/radeon/sid.h

@@ -424,6 +424,7 @@
 #       define RDERR_INT_ENABLE                         (1 << 0)
 #       define GUI_IDLE_INT_ENABLE                      (1 << 19)
 
+#define	CP_STRMOUT_CNTL					0x84FC
 #define	SCRATCH_REG0					0x8500
 #define	SCRATCH_REG1					0x8504
 #define	SCRATCH_REG2					0x8508