am33xx: support for booting via usbeth

This patch adds BOOT_DEVICE define for USB booting and fixes
spl_board_init function to call arch_misc_init (this is the place there
musb is initialized).
Signed-off-by: NIlya Yanok <ilya.yanok@cogentembedded.com>

arch/arm/cpu/armv7/omap-common/boot-common.c

@@ -55,6 +55,9 @@ void spl_board_init(void)
 #ifdef CONFIG_SPL_NAND_SUPPORT
 	gpmc_init();
 #endif
+#if defined(CONFIG_AM33XX) && defined(CONFIG_SPL_MUSB_NEW_SUPPORT)
+	arch_misc_init();
+#endif
 }
 
 int board_mmc_init(bd_t *bis)

arch/arm/include/asm/arch-am33xx/spl.h

@@ -29,6 +29,7 @@
 #define BOOT_DEVICE_MMC2	9	/* eMMC or daughter card */
 #define BOOT_DEVICE_SPI		11
 #define BOOT_DEVICE_UART	65
+#define BOOT_DEVICE_USBETH	68
 #define BOOT_DEVICE_CPGMAC	70
 #define BOOT_DEVICE_MMC2_2      0xFF
 #endif