arm: mx6: cm-fx6: map HDMI to IPU1 DI0 explicitly

U-Boot does not explicitly assign the display to an IPU interface. Instead, it
relies on the power-on default of DI0.

Since the kernel reassigns HDMI display to DI1, after a warm reset the HDMI
display no longer works in U-Boot.

Fix this by explicitly assigning HDMI to IPU1 DI0 in U-Boot.

Cc: Stefano Babic <sbabic@denx.de>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>

board/compulab/cm_fx6/cm_fx6.c

@@ -83,6 +83,7 @@ size_t display_count = ARRAY_SIZE(displays);
 static void cm_fx6_setup_display(void)
 {
 	struct mxc_ccm_reg *mxc_ccm = (struct mxc_ccm_reg *)CCM_BASE_ADDR;
+	struct iomuxc *const iomuxc_regs = (struct iomuxc *)IOMUXC_BASE_ADDR;
 	int reg;
 
 	enable_ipu_clock();
@@ -90,6 +91,7 @@ static void cm_fx6_setup_display(void)
 	reg = __raw_readl(&mxc_ccm->CCGR3);
 	reg |= MXC_CCM_CCGR3_IPU1_IPU_DI0_MASK;
 	writel(reg, &mxc_ccm->CCGR3);
+	clrbits_le32(&iomuxc_regs->gpr[3], MXC_CCM_CCGR3_IPU1_IPU_DI0_MASK);
 }
 #else
 static inline void cm_fx6_setup_display(void) {}