app/crypto-perf: fix CSV format

app/crypto-perf: fix CSV format

The format for printing float is incorrect for the following fields
in pmd-cyclecount test: Cycles/Op,Cycles/Enq,Cycles/Deq.

Currently, the format is %.f3. This format will round off the number to
the nearest integer and append a 3 after that.

This patch changes the format to %.3f. This will print the number as a
floating point with a precision of 3 fractional digits.

Fixes: 96dfeb609be1 ("app/crypto-perf: add new PMD benchmarking mode")
Cc: stable@dpdk.org
Signed-off-by: Ankur Dwivedi <adwivedi@marvell.com>
Signed-off-by: Anoob Joseph <anoobj@marvell.com>