arm: am33xx: Avoid writing into reserved DPLL divider

DPLL DRR doesn't have an M4 divider. But the clock driver is trying
to configure M4 divider as 4(writing into a reserved register).
Fixing it by making M4 divider as -1.
Reported-by: NSteve Kipisz <s-kipisz2@ti.com>
Signed-off-by: NLokesh Vutla <lokeshvutla@ti.com>

arch/arm/mach-omap2/am33xx/clock_am33xx.c

@@ -116,22 +116,22 @@ const struct dpll_params dpll_per_192MHz[NUM_CRYSTAL_FREQ] = {
 const struct dpll_params dpll_ddr3_303MHz[NUM_CRYSTAL_FREQ] = {
 		{505, 15, 2, -1, -1, -1, -1}, /*19.2*/
 		{101, 3, 2, -1, -1, -1, -1}, /* 24 MHz */
-		{303, 24, 1, -1, 4, -1, -1}, /* 25 MHz */
-		{303, 12, 2, -1, 4, -1, -1}  /* 26 MHz */
+		{303, 24, 1, -1, -1, -1, -1}, /* 25 MHz */
+		{303, 12, 2, -1, -1, -1, -1}  /* 26 MHz */
 };
 
 const struct dpll_params dpll_ddr3_400MHz[NUM_CRYSTAL_FREQ] = {
 		{125, 5, 1, -1, -1, -1, -1}, /*19.2*/
 		{50, 2, 1, -1, -1, -1, -1}, /* 24 MHz */
-		{16, 0, 1, -1, 4, -1, -1}, /* 25 MHz */
-		{200, 12, 1, -1, 4, -1, -1}  /* 26 MHz */
+		{16, 0, 1, -1, -1, -1, -1}, /* 25 MHz */
+		{200, 12, 1, -1, -1, -1, -1}  /* 26 MHz */
 };
 
 const struct dpll_params dpll_ddr2_266MHz[NUM_CRYSTAL_FREQ] = {
 		{665, 47, 1, -1, -1, -1, -1}, /*19.2*/
 		{133, 11, 1, -1, -1, -1, -1}, /* 24 MHz */
-		{266, 24, 1, -1, 4, -1, -1}, /* 25 MHz */
-		{133, 12, 1, -1, 4, -1, -1}  /* 26 MHz */
+		{266, 24, 1, -1, -1, -1, -1}, /* 25 MHz */
+		{133, 12, 1, -1, -1, -1, -1}  /* 26 MHz */
 };
 
 __weak const struct dpll_params *get_dpll_mpu_params(void)