ixgbe: fix maximum wait time in comment

As the code has changed the max wait time to 1000ms, the comment should
be changed accordingly.

Signed-off-by: Xiaolong Ye <xiaolong.ye@intel.com>
Acked-by: Qi Zhang <qi.z.zhang@intel.com>

Approved by: imp
Obtained from: DPDK (73247f1ced303c16987bb366d38a2d8a0fc40db4)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D31621

(cherry picked from commit 96ef6eb3ae9d622906fb838c82ede3074f864cdc)