cmdline: fix dynamic tokens parsing

cmdline: fix dynamic tokens parsing

When using dynamic tokens, the result buffer contains pointers to some
location inside the result buffer. When the content of the temporary
buffer is copied in the final one, these pointers still point to the
temporary buffer.

This works until the temporary buffer is kept intact, but the next
commit introduces a memset() that breaks this assumption.

This commit keeps the successfully parsed buffers, and ensures that the
pointers point to the valid location, by using temp buffer for following
parsing.

Fixes: 9b3fbb051d2e ("cmdline: fix parsing")
Cc: stable@dpdk.org
Signed-off-by: Xueming Li <xuemingl@mellanox.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>