imx: mx7dsabresd set wdog SRS bit

We use trigger pmic reset to reset the board, so set bit SRS to
disable internal WDOG_RESET_B_DEB to make reset stable.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Adrian Alonso <aalonso@freescale.com>
Tested-by: Fabio Estevam <fabio.estevam@freescale.com>

board/freescale/mx7dsabresd/mx7dsabresd.c

@@ -499,6 +499,8 @@ int power_init_board(void)
 
 int board_late_init(void)
 {
+	struct wdog_regs *wdog = (struct wdog_regs *)WDOG1_BASE_ADDR;
+
 #ifdef CONFIG_CMD_BMODE
 	add_board_boot_modes(board_boot_modes);
 #endif
@@ -509,7 +511,13 @@ int board_late_init(void)
 
 	imx_iomux_v3_setup_multiple_pads(wdog_pads, ARRAY_SIZE(wdog_pads));
 
-	set_wdog_reset((struct wdog_regs *)WDOG1_BASE_ADDR);
+	set_wdog_reset(wdog);
+
+	/*
+	 * Do not assert internal WDOG_RESET_B_DEB(controlled by bit 4),
+	 * since we use PMIC_PWRON to reset the board.
+	 */
+	clrsetbits_le16(&wdog->wcr, 0, 0x10);
 
 	return 0;
 }