netif/dc Updates

[Eduardo Tongson <propolice@xxxxxxxxx>]

* Fix a bug that could cause dc_stop() to try to m_freem() something that's
 not a valid mbuf pointer.
* Avoid an unnecessary copy of a packet if it is already in a single mbuf.
* Introduce an additional device flag (DC_TX_ALIGN) for those NICs which
 require the transmit buffers to be aligned to 32-bit boundaries.
* Ignore CSR13, CSR14, CSR15 'Media Specific Data' registers for 21143
 based cards which use SIA mode.
* Don't read the MAC address from a copy of the EEPROM in the softc
 that has been recorded earlier and overwrite it again later by
 reading it directly from the EEPROM again.
* Read the MAC address from the PAR0/PAR1 registers instead, which
 are autoloaded on reboot.
* Added ADMtek ADM9511 and ADM9513 device ID's

Taken-from: FreeBSD
           if_dc.c       1.9.46,48,49,50,51,52,53,55
           if_dcreg.h   1.4.2.23,24,25


<http://pornadmin.net/~tongson/bsd/dc-20050715.diff>

--ed
Eduardo Tongson