codec/encoder: loose the reference check
codec/encoder: loose the reference check

Allow prompting a warning like:

>>Warning:iNumRefFrame(3) setting does not support the temporal
>>and LTR setting, will be reset to 4

instead of reporting unsupported and fail.

Signed-off-by: Linjie Fu <d60fdfe6dda9e6e0a4eeba8048e65ca64f1dc752@zju.edu.cn>

mstorsjo/openh264,GuangweiWang/openh264,cisco/openh264,GuangweiWang/openh264,GuangweiWang/openh264,GuangweiWang/openh264,mstorsjo/openh264,cisco/openh264,cisco/openh264,mstorsjo/openh264,cisco/openh264,GuangweiWang/openh264,mstorsjo/openh264,mstorsjo/openh264,cisco/openh264,GuangweiWang/openh264,GuangweiWang/openh264,cisco/openh264,mstorsjo/openh264,mstorsjo/openh264,cisco/openh264