eventdev/eth_tx: fix adapter creation

eventdev/eth_tx: fix adapter creation

During adapter create, memory is allocated for storing event port
configuration which is freed during adapter free. The following
error is seen during free "EAL: Error: Invalid memory"

The service data pointer storage for txa_service_data_array is
allocated during adapter create with incorrect size which is less
than the required size.
Initialization of this memory causes buffer overflow and result in
metadata overwrite of event port config memory allocated above
and results in the above error message during free.

Allocating the correct size of memory for txa_service_data_array
prevents overwriting other memory areas like event port config
memory.

Fixes: a3bbf2e09756 ("eventdev: add eth Tx adapter implementation")
Cc: stable@dpdk.org
Signed-off-by: Naga Harish K S V <s.v.naga.harish.k@intel.com>
Acked-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>