powerpc/pseries/eeh: Fix pseries_eeh_err_inject

VFIO_EEH_PE_INJECT_ERR ioctl is currently failing on pseries
due to missing implementation of err_inject eeh_ops for pseries.
This patch implements pseries_eeh_err_inject in eeh_ops/pseries
eeh_ops. Implements support for injecting MMIO load/store error
for testing from user space.

The check on PCI error type (bus type) code is moved to platform
code, since the eeh_pe_inject_err can be allowed to more error
types depending on platform requirement. Removal of the check for
'type' in eeh_pe_inject_err() doesn't impact PowerNV as
pnv_eeh_err_inject() already has an equivalent check in place.

Signed-off-by: Narayana Murty N <nnmlinux@linux.ibm.com>
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240909140220.529333-1-nnmlinux@linux.ibm.com