ARM: rmobile: Add R-Car Generation 4 support

This adds R-Car Generation 4 (Gen4) support as Renesas ARM64 SoC.

In this version, reusing R-Car Gen3 lowlevel initialize routine [1]
and R-Car Gen3 memory map tables [2] .

[1] arch/arm/mach-rmobile/lowlevel_init_gen3.S
[2] arch/arm/mach-rmobile/memmap-gen3.c

Reviewed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
[Marek: - Enable DTO support by default
        - Sort the Kconfig lists
	- Select RCAR_64 Kconfig option to pull in all the shared
	  Kconfig options with Gen3, and use where applicable to
	  deduplicate entries.
	- Fix reference [2] typo in commit message
	- Drop config options moved to Kconfig, rename rest to CFG_
	  accordingly to synchronize with upstream changes. Drop
	  removed CONFIG_VERY_BIG_RAM.
        - Move board size limit to arch/Kconfig
	- Move GICR_BASE to headers instead of common config]
diff --git a/arch/arm/mach-rmobile/Makefile b/arch/arm/mach-rmobile/Makefile
index 5b86221..fadb6eb 100644
--- a/arch/arm/mach-rmobile/Makefile
+++ b/arch/arm/mach-rmobile/Makefile
@@ -10,7 +10,7 @@
 obj-$(CONFIG_TMU_TIMER) += ../../sh/lib/time.o
 obj-$(CONFIG_R8A7740) += lowlevel_init.o cpu_info-r8a7740.o pfc-r8a7740.o
 obj-$(CONFIG_RCAR_GEN2) += lowlevel_init_ca15.o cpu_info-rcar.o
-obj-$(CONFIG_RCAR_GEN3) += lowlevel_init_gen3.o cpu_info-rcar.o memmap-gen3.o
+obj-$(CONFIG_RCAR_64) += lowlevel_init_gen3.o cpu_info-rcar.o memmap-gen3.o
 obj-$(CONFIG_RZ_G2) += cpu_info-rzg.o
 
 ifneq ($(CONFIG_R8A779A0),)