davinci: Fix omapl138_lcdk builds

davinci: Fix omapl138_lcdk builds

The omapl138_lcdk platform is not a DA850 SoC so we need to select
SOC_DA8XX and not SOC_DA850, as it was before.  It does however point
out a bit of a misnomer in how all of these PLL defines are named as
they are generic to DA8xx, not DA850 centric.  Remove the 'if SOC_DA850'
under the defaults as these are simply the defaults.  As SOC_DA8XX will
select SYS_DA850_DDR_INIT when needed, we do not need it under both SOC
options.

Fixes: 76e22222d3aa ("Convert CONFIG_SYS_DV_CLKMODE et al to Kconfig")
Signed-off-by: Tom Rini <trini@konsulko.com>