mx6: iomux: add GPR1 defines for use with nitrogen6x

Select GPIO1 as the USB OTG ID pin for Nitrogen6x

Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
diff --git a/board/boundary/nitrogen6x/nitrogen6x.c b/board/boundary/nitrogen6x/nitrogen6x.c
index 1712908..daa3fc8 100644
--- a/board/boundary/nitrogen6x/nitrogen6x.c
+++ b/board/boundary/nitrogen6x/nitrogen6x.c
@@ -706,6 +706,13 @@
 
 int board_init(void)
 {
+	struct iomuxc_base_regs *const iomuxc_regs
+		= (struct iomuxc_base_regs *)IOMUXC_BASE_ADDR;
+
+	clrsetbits_le32(&iomuxc_regs->gpr[1],
+			IOMUXC_GPR1_OTG_ID_MASK,
+			IOMUXC_GPR1_OTG_ID_GPIO1);
+
 	/* address of boot parameters */
 	gd->bd->bi_boot_params = PHYS_SDRAM + 0x100;