ARM: shmobile: Add shared R-Car Gen2 CMA reservation code

Add R-Car Gen2 CMA memory reservation code that can be
shared between multiple SoCs and boards. At this point
r8a7790 and r8a7791 are supported.

The top 256MiB of the legacy 32-bit physical memory space
is assigned to a separate CMA area that may be assigned
to various devices later on.

Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
[horms+renesas@verge.net.au: rebased]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/arch/arm/mach-shmobile/setup-r8a7790.c b/arch/arm/mach-shmobile/setup-r8a7790.c
index 516b4e4..e190768 100644
--- a/arch/arm/mach-shmobile/setup-r8a7790.c
+++ b/arch/arm/mach-shmobile/setup-r8a7790.c
@@ -327,6 +327,7 @@
 	.init_early	= r8a7790_init_early,
 	.init_time	= rcar_gen2_timer_init,
 	.init_late	= shmobile_init_late,
+	.reserve	= rcar_gen2_reserve,
 	.dt_compat	= r8a7790_boards_compat_dt,
 MACHINE_END
 #endif /* CONFIG_USE_OF */