cris: add constfy to pgd_offset()
cris: add constfy to pgd_offset()

add constfy to pgd_offset() for avoid following warnings.

  CC      mm/pagewalk.o
mm/pagewalk.c: In function 'walk_page_range':
mm/pagewalk.c:111: warning: passing argument 1 of 'pgd_offset' discards qualifiers from p\
ointer target type

Signed-off-by: KOSAKI Motohiro <70a1d3ef3e17a2bb0f09a1b2e6c86f607ed1d6d9@jp.fujitsu.com>
Cc: Matt Mackall <4121265491a72225438dfd0e91a228f361407ae2@selenic.com>
Cc: "Vegard Nossum" <c9abf7248a519119ccb31f4fd3c3a4e0b6ebd20b@gmail.com>
Cc: Mikael Starvik <6c4d7924b92058127b0499322f0d64063fb5d591@axis.com>
Cc: Jesper Nilsson <987a7dbc972893e93e5578401bedc3a0f2ccb5e3@axis.com>
Signed-off-by: Andrew Morton <5c1e68b099950c134891f0b6e179498a8ebe9cf9@linux-foundation.org>
Signed-off-by: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs