MX28: Fixup the ad-hoc use of DIGCTL_MICROSECONDS

Use proper struct-based access for this register in the SPL code.

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

arch/arm/cpu/arm926ejs/mxs/spl_boot.c

@@ -38,12 +38,14 @@
  * takes a few seconds to roll. The boot doesn't take that long, so to keep the
  * code simple, it doesn't take rolling into consideration.
  */
-#define	HW_DIGCTRL_MICROSECONDS	0x8001c0c0
 void early_delay(int delay)
 {
-	uint32_t st = readl(HW_DIGCTRL_MICROSECONDS);
+	struct mxs_digctl_regs *digctl_regs =
+		(struct mxs_digctl_regs *)MXS_DIGCTL_BASE;
+
+	uint32_t st = readl(&digctl_regs->hw_digctl_microseconds);
 	st += delay;
-	while (st > readl(HW_DIGCTRL_MICROSECONDS))
+	while (st > readl(&digctl_regs->hw_digctl_microseconds))
 		;
 }