common: add new boot media kconfig entry

Add CONFIG_{SD|NAND|ONENAND|SPI|QSPI|SATA}_BOOT kconfig entries.

SoCs supports loading U-Boot from different medias to DRAM, such as
i.MX6/7 supports loading U-Boot to DRAM from sd/emmc/nand/qspi/spi/sata
and etc. For i.MX, imximage will generate different IVT headers according
to boot medias.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Heiko Schocher <hs@denx.de>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Christophe Ricard <christophe-h.ricard@st.com>
Cc: Nikita Kiryanov <nikita@compulab.co.il>
Cc: Francois Retief <fgretief@spaceteq.co.za>
Cc: Tom Rini <trini@konsulko.com>

common/Kconfig

@@ -108,6 +108,54 @@ config NOR_BOOT
 	  as the ROM only partially sets up pinmux.  We also default to using
 	  NOR for environment.
 
+config NAND_BOOT
+	bool "Support for booting from NAND flash"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via NAND flash. This is not a must, some SoCs need this,
+	  somes not.
+
+config ONENAND_BOOT
+	bool "Support for booting from ONENAND"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via ONENAND. This is not a must, some SoCs need this,
+	  somes not.
+
+config QSPI_BOOT
+	bool "Support for booting from QSPI flash"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via QSPI flash. This is not a must, some SoCs need this,
+	  somes not.
+
+config SATA_BOOT
+	bool "Support for booting from SATA"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via SATA. This is not a must, some SoCs need this,
+	  somes not.
+
+config SD_BOOT
+	bool "Support for booting from SD/EMMC"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via SD/EMMC. This is not a must, some SoCs need this,
+	  somes not.
+
+config SPI_BOOT
+	bool "Support for booting from SPI flash"
+	default n
+	help
+	  Enabling this will make a U-Boot binary that is capable of being
+	  booted via SPI flash. This is not a must, some SoCs need this,
+	  somes not.
+
 endmenu
 
 config BOOTDELAY