powerpc/eeh: Move PE state constants around

There are two equivalent sets of PE state constants, defined in
arch/powerpc/include/asm/eeh.h and include/uapi/linux/vfio.h.
Though the names are different, their corresponding values are
exactly same. The former is used by EEH core and the latter is
used by userspace.

The patch moves those constants from arch/powerpc/include/asm/eeh.h
to arch/powerpc/include/uapi/asm/eeh.h, which are expected to be
used by userspace from now on. We can't delete those constants in
vfio.h as it's uncertain that those constants have been or will be
used by userspace.

Suggested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>