i.MX31: Fix mx31_gpio_mux() function and MUX_-macros.

Correct the mx31_gpio_mux() function to allow changing all i.MX31 IOMUX
contacts instead of only the first 256 ones as is the case prior to
this patch.

Add missing MUX_* macros and update board files to use the new macros.

Signed-off-by: Magnus Lilja <lilja.magnus@gmail.com>
diff --git a/board/imx31_litekit/imx31_litekit.c b/board/imx31_litekit/imx31_litekit.c
index 8cbc26e..cb3e174 100644
--- a/board/imx31_litekit/imx31_litekit.c
+++ b/board/imx31_litekit/imx31_litekit.c
@@ -53,13 +53,13 @@
 	mx31_gpio_mux(MUX_CTS1__UART1_CTS_B);
 
 	/* SPI2 */
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_SS2);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_SCLK);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_SPI_RDY);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_MOSI);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_MISO);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_SS0);
-	mx31_gpio_mux((MUX_CTL_FUNC << 8) | MUX_CTL_CSPI2_SS1);
+	mx31_gpio_mux(MUX_CSPI2_SS2__CSPI2_SS2_B);
+	mx31_gpio_mux(MUX_CSPI2_SCLK__CSPI2_CLK);
+	mx31_gpio_mux(MUX_CSPI2_SPI_RDY__CSPI2_DATAREADY_B);
+	mx31_gpio_mux(MUX_CSPI2_MOSI__CSPI2_MOSI);
+	mx31_gpio_mux(MUX_CSPI2_MISO__CSPI2_MISO);
+	mx31_gpio_mux(MUX_CSPI2_SS0__CSPI2_SS0_B);
+	mx31_gpio_mux(MUX_CSPI2_SS1__CSPI2_SS1_B);
 
 	/* start SPI2 clock */
 	__REG(CCM_CGR2) = __REG(CCM_CGR2) | (3 << 4);