e1000e: Fix PBACLR implementation

This patch fixes incorrect check for
interrypt type being used.

PBSCLR register is valid for MSI-X only.

See spec. 10.2.3.13 MSI—X PBA Clear

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>