feat(plat/rcar3): keep RWDT enabled

In case the WDT is enabled by prior stage, keep it enabled.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Change-Id: Ie7c0eaf2f59dd8c30a9ef686a7000424f38d6352
diff --git a/plat/renesas/common/bl2_cpg_init.c b/plat/renesas/common/bl2_cpg_init.c
index a6579eb..a545f71 100644
--- a/plat/renesas/common/bl2_cpg_init.c
+++ b/plat/renesas/common/bl2_cpg_init.c
@@ -139,7 +139,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x040E2FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x80000004U);
+	cpg_write(SMSTPCR4, 0x80000000U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0xC3FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);
@@ -175,7 +175,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x040E2FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x80000004U);
+	cpg_write(SMSTPCR4, 0x80000000U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0xC3FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);
@@ -211,7 +211,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x040E2FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x80000004U);
+	cpg_write(SMSTPCR4, 0x80000000U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0xC3FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);
@@ -245,7 +245,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x340E2FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x80000004U);
+	cpg_write(SMSTPCR4, 0x80000000U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0xC3FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);
@@ -279,7 +279,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x000E2FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x80000004U);
+	cpg_write(SMSTPCR4, 0x80000000U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0xC3FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);
@@ -298,7 +298,7 @@
 	cpg_write(SMSTPCR1, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR2, 0x00060FDCU);
 	cpg_write(SMSTPCR3, 0xFFFFFBDFU);
-	cpg_write(SMSTPCR4, 0x00000084U);
+	cpg_write(SMSTPCR4, 0x00000080U | (mmio_read_32(SMSTPCR4) & 0x4));
 	cpg_write(SMSTPCR5, 0x83FFFFFFU);
 	cpg_write(SMSTPCR6, 0xFFFFFFFFU);
 	cpg_write(SMSTPCR7, 0xFFFFFFFFU);