net/mlx4_core: Make explicit conversion to 64bit value

The "lg" variable is declared as int so in all places where this variable
is used as a shift operand, the output will be int too.

This produces the following smatch warning:
drivers/net/ethernet/mellanox/mlx4/fw.c:1532 mlx4_map_cmd() warn:
	should '1 << lg' be a 64 bit type?

Simple declaration of "1" to be "1ULL" will fix the issue.

Fixes: 225c7b1f

 ("IB/mlx4: Add a driver Mellanox ConnectX InfiniBand adapters")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>