Fix io ordering problems in e100

Checking e100.c code against Documentation/io_ordering.txt I found the
following problem:

spin_lock_irq...
write
spin-unlock
e100_write_flush

The attached patch fix the code like this:

spin_lock_irq...
write
e100_write_flush
spin-unlock

Signed-off-by: Catalin BOIE <catab@umbrella.ro>
Signed-off-by: Jeff Garzik <jeff@garzik.org>