make bnx2x select ZLIB_INFLATE

The bnx2x module depends on the zlib_inflate functions.  The
build will fail if ZLIB_INFLATE has not been selected manually
or by building another module that automatically selects it.

Modify BNX2X config option to 'select ZLIB_INFLATE' like BNX2
and others.  This seems to fix it.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Eliezer Tamir <eliezert@broadcom.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>