drivers/char/mem.c: cleanups

- fix switch statement layout

- fix whitespace stuff

- fix comment layout

- remove unneeded inlining

- use __weak

- remove trailing whitespace

- move uncached_access() inside `#ifndef __HAVE_PHYS_MEM_ACCESS_PROT' - it
  is otherwise unused.

Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>