ARM: rmobile: Zap RCAR_GEN3_EXTRAM_BOOT

This Kconfig option is not used on any board, so drop it.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx@renesas.com>
Cc: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>

arch/arm/mach-rmobile/Kconfig.64

@@ -18,11 +18,6 @@ endchoice
 config SYS_SOC
 	default "rmobile"
 
-config RCAR_GEN3_EXTRAM_BOOT
-	bool "Enable boot from RAM"
-	depends on TARGET_SALVATOR_X
-	default n
-
 source "board/renesas/salvator-x/Kconfig"
 
 endif