Provide a binary to hex conversion function

Provide a function to convert a buffer of binary data into an unterminated
ascii hex string representation of that data.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

diff --cc include/linux/kernel.h
Simple merge

diff --cc lib/hexdump.c
Simple merge