vdpa/pds: use %pe for ERR_PTR() in event handler registration

vdpa/pds: use %pe for ERR_PTR() in event handler registration

Use %pe instead of %ps when printing ERR_PTR() values. %ps is intended
for string pointers, while %pe correctly prints symbolic error names
for error pointers returned via ERR_PTR().
This shows the returned error value more clearly.

Fixes: 67f27b8b3a34 ("pds_vdpa: subscribe to the pds_core events")
Signed-off-by: Alok Tiwari <alok.a.tiwari@oracle.com>
Reviewed-by: Brett Creeley <brett.creeley@amd.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20251018174705.1511982-1-alok.a.tiwari@oracle.com>