fixed the error in Intel(R) Xeon(R) Gold 6152 CPU like:
[libaom-av1 @ 0x469f340] Failed to initialize encoder: Invalid parameter
[libaom-av1 @ 0x469f340]   Additional information: g_threads out of range [..MAX_NUM_THREADS]
Signed-off-by: Jun Zhao <mypopydev@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>