powerpc/pseries: Return -EIO instead of -EINTR for H_ABORTED error

Some commands for eg. "cat" might continue to retry on encountering
EINTR. This is not expected for original error code H_ABORTED.

Map H_ABORTED to more relevant Linux error code EIO.

Fixes: 2454a7af ("powerpc/pseries: define driver for Platform KeyStore")
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221106205839.600442-4-nayna@linux.ibm.com