powerpc/km82xx: rework DIP switch detection

Introduce a struct for the BFTICU FPGA to increase the readability of
the code. And the define CONFIG_SYS_BFTICU_BASE was removed because
the CONFIG_SYS_FPGA_BASE is already the base value for BFTICU registers.

Signed-off-by: Andreas Huber <andreas.huber@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Acked-by: Heiko Schocher <hs@denx.de>
cc: Wolfgang Denk <wd@denx.de>
cc: Detlev Zundel <dzu@denx.de>
diff --git a/board/keymile/km82xx/km82xx.c b/board/keymile/km82xx/km82xx.c
index 6c511a6..01c0bfd 100644
--- a/board/keymile/km82xx/km82xx.c
+++ b/board/keymile/km82xx/km82xx.c
@@ -296,15 +296,14 @@
 	return 0;
 }
 
-#define DIPSWITCH_OFFSET 0x89
-#define DIPSWITCH_MASK   0x0f
-
 int last_stage_init(void)
 {
+	struct bfticu_iomap *base =
+		(struct bfticu_iomap *)CONFIG_SYS_FPGA_BASE;
 	u8 dip_switch;
-	/* Dip switch */
-	dip_switch = readb(CONFIG_SYS_BFTICU_BASE + DIPSWITCH_OFFSET);
-	dip_switch &= DIPSWITCH_MASK;
+
+	dip_switch = in_8(&base->mswitch);
+	dip_switch &= BFTICU_DIPSWITCH_MASK;
 	/* dip switch 'full reset' or 'db erase' */
 	if (dip_switch & 0x1 || dip_switch & 0x2) {
 		/* start bootloader */