vTPM: support little endian guests

This patch makes the code endianness independent. We defined a
macro do_endian_conversion to apply endianness to raw integers
in the event entries so that they will be displayed properly.
tpm_binary_bios_measurements_show() is modified for the display.

Signed-off-by: Hon Ching(Vicky) Lo <honclo@linux.vnet.ibm.com>
Signed-off-by: Joy Latten <jmlatten@linux.vnet.ibm.com>
Reviewed-by: Ashley Lai <ashley@ahsleylai.com>
Reviewed-by: Ashley Lai <ashley@ahsleylai.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>