feat(imx8mq): enable dram dvfs support on imx8mq

Enable DRAM DVFS support on i.MX8MQ.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: Id72c5eb9625936052ec51e5a52d9d31175ed1b1b
diff --git a/plat/imx/common/imx_sip_svc.c b/plat/imx/common/imx_sip_svc.c
index a816c80..6d6633c 100644
--- a/plat/imx/common/imx_sip_svc.c
+++ b/plat/imx/common/imx_sip_svc.c
@@ -36,6 +36,8 @@
 	case IMX_SIP_GPC:
 		SMC_RET1(handle, imx_gpc_handler(smc_fid, x1, x2, x3));
 		break;
+	case IMX_SIP_DDR_DVFS:
+		return dram_dvfs_handler(smc_fid, handle, x1, x2, x3);
 #endif
 #if defined(PLAT_imx8mm) || defined(PLAT_imx8mn) || defined(PLAT_imx8mp)
 	case IMX_SIP_DDR_DVFS: