MIPS: BCM63xx: Remove duplicate CONFIG_CMDLINE.

Builtin cmdline is copied by arch_mem_init().

Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/812/


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