[PATCH] declance: Fix PMAX and PMAD support

The shared buffer used by the LANCE on the PMAX only supports halfword
(16-bit) accesses.  And the PMAD has the buffer wired differently.  This is
a change to fix these issues.

Tested with a DECstation 2100 (thanks Flo for making this possible) and a
DECstation 5000/133 (both the PMAD and the onboard LANCE).
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Jeff Garzik <jeff@garzik.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>