sis900 defines 'cfgpmcsr' as an I/O space register, but CFGPMCSR is
in fact a config space register, and there is no register at offset
0x44 in I/O space, so delete the enum.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Jeff Garzik <jgarzik@pobox.com>