ARM: i.MX IOMUX-V3 replace struct pad_desc with bitmapped cookie

The following patch is a first step to convert the 'struct pad_desc'
to a bitmapped cookie to facilitate adding platform specific pullup or
drive strength definitions to existing pad definitions without need to
rewrite the complete pad def.

The patch wraps 'struct pad_desc' in an opaque data type and
introduces macros to access the individual members.
This patch does not constitute any functional change!

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/mach-imx/mach-mx25_3ds.c b/arch/arm/mach-imx/mach-mx25_3ds.c
index 52b4d9b..8b8e75b 100644
--- a/arch/arm/mach-imx/mach-mx25_3ds.c
+++ b/arch/arm/mach-imx/mach-mx25_3ds.c
@@ -47,7 +47,7 @@
 	.flags = IMXUART_HAVE_RTSCTS,
 };
 
-static struct pad_desc mx25pdk_pads[] = {
+static iomux_v3_cfg_t mx25pdk_pads[] = {
 	MX25_PAD_FEC_MDC__FEC_MDC,
 	MX25_PAD_FEC_MDIO__FEC_MDIO,
 	MX25_PAD_FEC_TDATA0__FEC_TDATA0,