plat/intel: Fix SMPLSEL for MMC

MMC sample select needs to be set properly so that DWMMC clock can be
driven to 50Mhz

Signed-off-by: Tien Hock, Loh <tien.hock.loh@intel.com>
Change-Id: I4a1dde4f6a1e78a36940c57a7a5b162be0bd443a

plat/intel/soc/stratix10/include/s10_system_manager.h

@@ -59,6 +59,11 @@
 #define S10_CCU_NOC_CPU0_RAMSPACE0_0		0xf7004688
 #define S10_CCU_NOC_IOM_RAMSPACE0_0		0xf7018628
 
+#define S10_SYSMGR_CORE(x)			(0xffd12000 + (x))
+#define SYSMGR_MMC				0x28
+#define SYSMGR_MMC_DRVSEL(x)			(((x) & 0x7) << 0)
+
+
 #define DISABLE_L4_FIREWALL	(BIT(0) | BIT(16) | BIT(24))
 
 void enable_nonsecure_access(void);

plat/intel/soc/stratix10/soc/s10_system_manager.c

@@ -86,5 +86,8 @@ void enable_nonsecure_access(void)
 
 	mmio_clrbits_32(S10_CCU_NOC_CPU0_RAMSPACE0_0, 0x03);
 	mmio_clrbits_32(S10_CCU_NOC_IOM_RAMSPACE0_0, 0x03);
+
+	mmio_write_32(S10_SYSMGR_CORE(SYSMGR_MMC), SYSMGR_MMC_DRVSEL(3));
+
 }