w1: support auto-load of w1_bq27000 module.

1/ change request_module call to zero-pad single digit
   family numbers.  This appears to be the intention of
   the code, but not what it actually does.

   This means that the alias created for W1_FAMILY_SMEM_01
   might actually be useful.

2/ Define a family name for the BQ27000 battery charge monitor.
   Unfortunately this is the same number as W1_FAMILY_SMEM_01
   so if both a compiled on a system, one module might need to
   be blacklisted.

3/ Add a MODULE_ALIAS for the bq27000.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>