param: make param sections const.

Since this section can be read-only (they're in .rodata), they should
always have been const.  Minor flow-through various functions.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Phil Carmody <ext-phil.2.carmody@nokia.com>

diff --cc include/linux/moduleparam.h
Simple merge

diff --cc init/main.c
Simple merge

diff --cc kernel/params.c
Simple merge