lightnvm: remove unused 'geo' variable

A previous commit correctly removed set-but-not-read variables, but
this left two new variables now unused. Kill them.

Fixes: ba6f7da9

 ("lightnvm: remove set but not used variables 'data_len' and 'rq_len'")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <axboe@kernel.dk>