ixgbe: Be explict with what we are !'ing in ixgbe_sfp_config_module_task()

GCC warns:
drivers/net/ixgbe/ixgbe_main.c: In function 'ixgbe_sfp_config_module_task':
drivers/net/ixgbe/ixgbe_main.c:3920: warning: suggest parantheses around
operand of '!' or change '&' to '&&' or '!' to '~'

Which I think is right.  Bracket to remove ambiguity.

Signed-off-by: Tony Breeds <tony@bakeyournoodle.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>