e1000: Mask registers when writing

When a register has effective bits fewer than their width, the old code
inconsistently masked when writing or reading. Make the code consistent
by always masking when writing, and remove some code duplication.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
1 file changed