pata_hpt37x: fold 'if' statement into 'switch'

hpt37x_init_one() has a large *if* statement which should really be folded into
the *switch* statement that currently constitutes its *else* branch, reducing
one level of indentation...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>