feat(imx8mq): correct the slot ack setting for STOP mode

A53 core's power up ack need to be used when system resume
from DSM mode.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: I47fb33c0582ae5f483ffaa887f95e27bd47875f7
diff --git a/plat/imx/imx8m/include/gpc.h b/plat/imx/imx8m/include/gpc.h
index e5af4b4..eb33abd 100644
--- a/plat/imx/imx8m/include/gpc.h
+++ b/plat/imx/imx8m/include/gpc.h
@@ -24,6 +24,7 @@
 #define COREx_LPM_PUP(core_id)		((core_id) < 2 ? (1 << ((core_id) * 2 + 9)) : (1 << ((core_id) * 2 + 21)))
 #define SLTx_CFG(n)			((SLT0_CFG + ((n) * 4)))
 #define SLT_COREx_PUP(core_id)		(0x2 << ((core_id) * 2))
+#define SLT_COREx_PUP_ACK(core_id)	((core_id) < 2 ? (1 << ((core_id) + 16)) : (1 << ((core_id) + 27)))
 
 #define IMR_MASK_ALL	0xffffffff