ARM: imx6: DHCOM i.MX6 PDK: enable pad pull ups of SS lines of spi used for boot

It turned out that after a reset the boot process from the spi bootflash is
disturbed by other spi slave devices connected to DHCOM SPI1, which uses the
same spi interface with a different SS line.

Therefore the pad pull ups are enabled.

Signed-off-by: Ludwig Zenz <lzenz@dh-electronics.com>
diff --git a/board/dhelectronics/dh_imx6/dh_imx6_spl.c b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
index b492961..1b7acc8 100644
--- a/board/dhelectronics/dh_imx6/dh_imx6_spl.c
+++ b/board/dhelectronics/dh_imx6/dh_imx6_spl.c
@@ -440,8 +440,13 @@
 
 /* SPI */
 static iomux_v3_cfg_t const ecspi1_pads[] = {
-	/* SS0 */
-	IOMUX_PADS(PAD_EIM_EB2__GPIO2_IO30	| MUX_PAD_CTRL(SPI_PAD_CTRL)),
+	/* SS0 - SS of boot flash */
+	IOMUX_PADS(PAD_EIM_EB2__GPIO2_IO30	|
+		MUX_PAD_CTRL(SPI_PAD_CTRL | PAD_CTL_PUS_100K_UP)),
+	/* SS2 - SS of DHCOM SPI1 */
+	IOMUX_PADS(PAD_KEY_ROW2__GPIO4_IO11	|
+		MUX_PAD_CTRL(SPI_PAD_CTRL | PAD_CTL_PUS_100K_UP)),
+
 	IOMUX_PADS(PAD_EIM_D17__ECSPI1_MISO	| MUX_PAD_CTRL(SPI_PAD_CTRL)),
 	IOMUX_PADS(PAD_EIM_D18__ECSPI1_MOSI	| MUX_PAD_CTRL(SPI_PAD_CTRL)),
 	IOMUX_PADS(PAD_EIM_D16__ECSPI1_SCLK	| MUX_PAD_CTRL(SPI_PAD_CTRL)),