davinci: Enable DDR_INIT for DA8XX

Commit 6aa4ad8e38 ("Convert CONFIG_SOC_DA8XX et al to Kconfig")
converted SOC_DA8XX to Kconfig but missed enabling DDR_INIT for
SOC_DA8XX, which broke OMAPL138 to boot.

Commit 2e87980580 ("davinci: Fix omapl138_lcdk builds") disabled
DDR_INIT for all DA850 SoCs. This failed all DA850 boards to boot
as ddr is not being initialized.

Enable SYS_DA850_DDR_INIT for DA8XX so that all DA850 and OMAPL138
will have ddr initialized

Fixes: 2e87980580 ("davinci: Fix omapl138_lcdk builds")
Fixes: 6aa4ad8e38 ("Convert CONFIG_SOC_DA8XX et al to Kconfig")
Reported-by: Sekhar Nori <nsekhar@ti.com>
Tested-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Reviewed-by: David Lechner <david@lechnology.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

arch/arm/mach-davinci/Kconfig

@@ -58,6 +58,7 @@ config SOC_DA850
 config SOC_DA8XX
 	bool
 	select SYS_DA850_PLL_INIT if SUPPORT_SPL || DA850_LOWLEVEL
+	select SYS_DA850_DDR_INIT if SUPPORT_SPL || DA850_LOWLEVEL
 
 config MACH_DAVINCI_DA850_EVM
 	bool