mlxsw: reg: Fix SPVM max record count

mlxsw: reg: Fix SPVM max record count

[ Upstream commit f004ec065b4879d6bc9ba0211af2169b3ce3097f ]

The num_rec field is 8 bit, so the maximal count number is 255. This
fixes vlans not being enabled for wider ranges than 255.

Fixes: b2e345f9a454 ("mlxsw: reg: Add Switch Port VID and Switch Port VLAN Membership registers definitions")
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>