CLASS-sysfs.c is a common idiom for linux subsystems.

This is the first step to pulling all the sysfs support code from
the drivers into tpm-sysfs. This is a plain text copy from tpm-interface
with support changes to make it compile.

_tpm_pcr_read is made non-static and is called tpm_pcr_read_dev.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>