debugfs: bugfix: include <linux/io.h> in file.c
debugfs: bugfix: include <linux/io.h> in file.c

The regs32 machinery uses readl. I forgot the mandatory include
and the code was not compiling on all archs.

Reported-by: Stephen Rothwell <4bf0fb350827ce8d86875e76c923a478597c3cef@canb.auug.org.au>
Signed-off-by: Alessandro Rubini <bc08dd6b821ed1cc3641822f9bf2e85bb4fd6e75@gnudd.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@suse.de>

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