i.MX28: Shut down the LCD controller before reset

If the LCD controller is on before the CPU goes into reset, the traffic on LCDIF
data pins interferes with the BootROM's boot mode sampling. So shut the
controller down.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Detlev Zundel <dzu@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>

arch/arm/cpu/arm926ejs/mx28/mx28.c

@@ -51,9 +51,16 @@ void reset_cpu(ulong ignored) __attribute__((noreturn));
 
 void reset_cpu(ulong ignored)
 {
-
 	struct mx28_rtc_regs *rtc_regs =
 		(struct mx28_rtc_regs *)MXS_RTC_BASE;
+	struct mx28_lcdif_regs *lcdif_regs =
+		(struct mx28_lcdif_regs *)MXS_LCDIF_BASE;
+
+	/*
+	 * Shut down the LCD controller as it interferes with BootROM boot mode
+	 * pads sampling.
+	 */
+	writel(LCDIF_CTRL_RUN, &lcdif_regs->hw_lcdif_ctrl_clr);
 
 	/* Wait 1 uS before doing the actual watchdog reset */
 	writel(1, &rtc_regs->hw_rtc_watchdog);