arm, da850: enable the correct uart in arch_cpu_init()

in arch_cpu_init() uart2 is fix enabled, without reference the
setting from CONFIG_SYS_NS16550_COM1. Use the setting from
CONFIG_SYS_NS16550_COM1 for enabling the console.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Tom Rini <tom.rini@gmail.com>
Cc: Christian Riesch <christian.riesch@omicron.at>