of: make sure of_alias is initialized before accessing it

Simply swap of_alias and of_chosen initialization so
that of_alias ends up read first. This must be done
because it is accessed couple of lines below when
trying to initialize the of_stdout using the alias
based legacy method.

[Fixes a752ee56 - tty: Update hypervisor tty drivers to
use core stdout parsing code]

Signed-off-by: Laurentiu Tudor <Laurentiu.Tudor@freescale.com>
[glikely: Don't move the 'if (!of_aliases)' test]
Signed-off-by: Grant Likely <grant.likely@linaro.org>