app/testpmd: fix access to DSCP table entries

app/testpmd: fix access to DSCP table entries

During parsing of DSCP entries, memory is allocated and assigned
to *dscp_table. Later on, same memory is accessed using
*dscp_table[i++].

Due to higher precedence for array subscript, dscp_table[i++] will
be executed first which actually does not point to the same memory
which was allocated previously for DSCP table entries.

Fixes: 459463ae6c26 ("app/testpmd: fix memory allocation for DSCP table")
Cc: stable@dpdk.org
Signed-off-by: Sunil Kumar Kori <skori@marvell.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>