Convert CONFIG_AT91_EFLASH to Kconfig

This converts the following to Kconfig:
   CONFIG_AT91_EFLASH

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stefan Roese <sr@denx.de>
Acked-by: Eugen Hristev <eugen.hristev@microchip.com>

arch/arm/mach-at91/Kconfig

@@ -302,6 +302,14 @@ config ATMEL_SFR
 config SYS_SOC
 	default "at91"
 
+config AT91_EFLASH
+	bool "Support AT91 flash driver"
+	depends on AT91SAM9XE
+	select USE_SYS_MAX_FLASH_BANKS
+	help
+	  Enable the driver for the embedded flash used in the Atmel
+	  AT91SAM9XE devices.
+
 source "board/atmel/at91sam9260ek/Kconfig"
 source "board/atmel/at91sam9261ek/Kconfig"
 source "board/atmel/at91sam9263ek/Kconfig"

configs/ethernut5_defconfig

@@ -4,6 +4,7 @@ CONFIG_ARCH_CPU_INIT=y
 CONFIG_ARCH_AT91=y
 CONFIG_SYS_TEXT_BASE=0x27000000
 CONFIG_SYS_MALLOC_LEN=0x121000
+CONFIG_AT91_EFLASH=y
 CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_TARGET_ETHERNUT5=y
 CONFIG_NR_DRAM_BANKS=1
@@ -66,7 +67,6 @@ CONFIG_SYS_I2C_SOFT_SLAVE=0
 CONFIG_GENERIC_ATMEL_MCI=y
 CONFIG_MTD=y
 CONFIG_MTD_NOR_FLASH=y
-CONFIG_USE_SYS_MAX_FLASH_BANKS=y
 CONFIG_MTD_RAW_NAND=y
 # CONFIG_SYS_NAND_USE_FLASH_BBT is not set
 CONFIG_NAND_ATMEL=y

include/configs/ethernut5.h

@@ -33,7 +33,6 @@
 
 /* 512kB on-chip NOR flash */
 # define CONFIG_SYS_FLASH_BASE		0x00200000 /* AT91SAM9XE_FLASH_BASE */
-# define CONFIG_AT91_EFLASH
 # define CONFIG_SYS_MAX_FLASH_SECT	32
 # define CONFIG_EFLASH_PROTSECTORS	1
 

scripts/config_whitelist.txt

@@ -18,7 +18,6 @@ CONFIG_AT91SAM9G20EK
 CONFIG_AT91SAM9G20EK_2MMC
 CONFIG_AT91SAM9G45_LCD_BASE
 CONFIG_AT91SAM9M10G45EK
-CONFIG_AT91_EFLASH
 CONFIG_AT91_GPIO_PULLUP
 CONFIG_AT91_LED
 CONFIG_AT91_WANTS_COMMON_PHY