- Provide mxge_get_counter() to return counters that are not collected,
  but taken from hardware.
- Mechanically convert to if_inc_counter() the rest of counters.
Whitespace cleanup.
Run through unifdef(1) with slight hand-editing after. It is obvious,
that the driver is not going to be ever improved in terms of hardware
support, it is going to be only maintained as our kernel APIs change.
Carrying all the compatibility with ancient versions of NetBSD, OpenBSD,
Linux and BSDI, as well as obsoleted FreeBSD versions has no reason.
- Provide lmc_get_counter() to return counters that are not collected,
  but taken from hardware.
- Mechanically convert to if_inc_counter() the rest of counters.
- Provide bce_get_counter() to return counters that are not collected,
  but taken from hardware.
- Mechanically convert to if_inc_counter() the rest of counters.
- While here fix 3 instances of the same bug, when error counter was ++
  in one place and then assigned in other place, losing the increment.
  Achieve that storing soft errors counters in softc.
ddb: allow specifying the exact address of the symtab and strtab

When the FreeBSD kernel is loaded from Xen the symtab and strtab are
not loaded the same way as the native boot loader. This patch adds
three new global variables to ddb that can be used to specify the
exact position and size of those tables, so they can be directly used
as parameters to db_add_symbol_table. A new helper is introduced, so callers
that used to set ksym_start and ksym_end can use this helper to set the new
variables.

It also adds support for loading them from the Xen PVH port, that was
previously missing those tables.

Sponsored by: Citrix Systems R&D
Reviewed by:	kib

ddb/db_main.c:
 - Add three new global variables: ksymtab, kstrtab, ksymtab_size that
   can be used to specify the position and size of the symtab and
   strtab.
 - Use those new variables in db_init in order to call db_add_symbol_table.
 - Move the logic in db_init to db_fetch_symtab in order to set ksymtab,
   kstrtab, ksymtab_size from ksym_start and ksym_end.

ddb/ddb.h:
 - Add prototype for db_fetch_ksymtab.
 - Declate the extern variables ksymtab, kstrtab and ksymtab_size.

x86/xen/pv.c:
 - Add support for finding the symtab and strtab when booted as a Xen
   PVH guest. Since Xen loads the symtab and strtab as NetBSD expects
   to find them we have to adapt and use the same method.

amd64/amd64/machdep.c:
arm/arm/machdep.c:
i386/i386/machdep.c:
mips/mips/machdep.c:
pc98/pc98/machdep.c:
powerpc/aim/machdep.c:
powerpc/booke/machdep.c:
sparc64/sparc64/machdep.c:
 - Use the newly introduced db_fetch_ksymtab in order to set ksymtab,
   kstrtab and ksymtab_size.
Provide vmxnet3_get_counter() to return counters that are not collected,
but taken from hardware.