MIPS: ralink: Cosmetic change to prom_init().

Over the years the code has been changed various times leading to
argc/argv being defined in a different function to where we actually
use the variables. Clean this up by moving them to prom_init_cmdline().

Signed-off-by: John Crispin <john@phrozen.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14902/


Signed-off-by: Ralf Baechle <ralf@linux-mips.org>