Fix some FRV arch compile errors, including:

 (*) Marking nr_kernel_pages as __meminitdata so that references to it end up
     being properly calculated rather than being assumed to be in the small
     data section (and thus calculated wrt the GP register).  Not doing this
     causes the linker to emit errors as the offset is too big to fit into the
     load instruction.

 (*) Move pm_power_off into an unconditionally compiled .c file as it's now
     unconditionally accessed.

 (*) Declare frv_change_cmode() in a header file rather than in a .c file, and
     declare it asmlinkage.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>