ixgb: convert boolean_t to bool

> send me a patch for e1000 and for ixgb and I'll happily apply those :)

boolean_t to bool
TRUE to true
FALSE to false

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>