eal/linux: remove useless unlock of hugepage when clearing

eal/linux: remove useless unlock of hugepage when clearing

Coverity was complaining about not checking result of call to
fcntl() for unlocking the file. Disregarding the fact that error
value returned from fcntl() unlock call is highly unlikely in the
first place, we are subsequently calling close() on that same fd,
which will drop the lock, which makes call to fcntl() unnecessary.

Fix this by removing a call to fcntl() altogether.

Coverity issue: 272607
Fixes: 66cc45e293ed ("mem: replace memseg with memseg lists")

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>