[PATCH] pcnet32: show name of failing device

Display the name eth%d or pci_name() of device which fails to allocate
memory.  When changing ring size via ethtool, it also releases the
lock before returning on error.  Added comment that the caller of
pcnet32_alloc_ring must call pcnet32_free_ring on error, to avoid leak.
Tested ia32 by forcing allocation errors.

Signed-off-by: Don Fry <brazilnut@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>