accel_perf: Fix the complier complaining.

Faced the following warnings during the compilation:

accel_perf.c:222:17: warning: ‘argval’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  222 |   g_crc32c_seed = argval;

And this patch can be used to fix this issue.

Change-Id: I84ee542d629ff5d9e6a2873c0035bea81b376150
Signed-off-by: Ziye Yang <ziye.yang@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/8538


Reviewed-by:  <dongx.yi@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Chengqiang Meng <chengqiangx.meng@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: wanghailiang <hailiangx.e.wang@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Community-CI: Mellanox Build Bot