[SCSI] fcoe: Remove mutex_trylock/restart_syscall checks

These checks were initially added to avoid a lockdep
false positive when dealing with the s_active, rtnl
and fcoe_config_mutex mutexes. Recently the create,
destroy, enable and disable sysfs entries were moved
from fcoe.ko to libfcoe.ko. With this change the mutex
usage was shuffled around and the lockdep false
positive stopped happening. We can now remove these
checks.

Signed-off-by: Robert Love <robert.w.love@intel.com>
Tested-by: Ross Brattain <ross.b.brattain@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>