reiserfs: rename p_s_inode to inode

This patch is a simple s/p_s_inode/inode/g to the reiserfs code.  This
is the third in a series of patches to rip out some of the awful
variable naming in reiserfs.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>