compress/octeontx: fix global variable multiple definitions

compress/octeontx: fix global variable multiple definitions

'octtx_zip_logtype_driver' global variable is defined in a header file
which was causing multiple definitions of the variable, fixed it by
moving it to the .c file.

Issue has been detected by '-fno-common' gcc flag.

Fixes: 43e610bb8565 ("compress/octeontx: introduce octeontx zip PMD")
Cc: stable@dpdk.org
Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Ashish Gupta <ashishg@marvell.com>