doc: remove unneeded TLB from FAQ question 2

Hugepages are just that, hugepages. The TLB is a sort of cache for doing
address translation and does not need to be referenced in the title, since
"TLB hugepages" doesn't make any sense (as there are no non-TLB hugepages
that you can allocate).

Fixes: 6e718ae062d0 ("doc: release notes 1.7")

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>