arm: mvebu: fix boot from UART on ClearFog Base

The ClearFog Base boot from UART when setting the DIP switches to 01001.
Unfortunately, the SPL code sometimes fails to detect the UART boot
method at run-time. Add an alternative SAR UART boot value to fix this.

Note that this alternative value is not documented (Armada 38x Hardware
Specifications, Table 48). But experimentations showed it on the
ClearFog Base.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Stefan Roese <sr@denx.de>

arch/arm/mach-mvebu/include/mach/soc.h

@@ -142,6 +142,7 @@
 #define BOOT_DEV_SEL_MASK	(0x3f << BOOT_DEV_SEL_OFFS)
 
 #define BOOT_FROM_UART		0x28
+#define BOOT_FROM_UART_ALT	0x3f
 #define BOOT_FROM_SPI		0x32
 #define BOOT_FROM_MMC		0x30
 #define BOOT_FROM_MMC_ALT	0x31

arch/arm/mach-mvebu/spl.c

@@ -42,6 +42,9 @@ static u32 get_boot_device(void)
 		return BOOT_DEVICE_MMC1;
 #endif
 	case BOOT_FROM_UART:
+#ifdef BOOT_FROM_UART_ALT
+	case BOOT_FROM_UART_ALT:
+#endif
 		return BOOT_DEVICE_UART;
 	case BOOT_FROM_SPI:
 	default: