obs-ffmpeg: Cap AMF encoder at 100 Mbps

The AMF docs specify that the maximum value for TARGET_BITRATE and
PEAK_BITRATE is 100,000,000 bit/s. Trying to set values above this
maximum value results in AMF choosing from its defaults instead of
capping at the maximum value. Let's cap at 100,000 Kbps in the UI to
prevent users from running in to this.

Fixes GitHub Issue obsproject/obs-studio#7423.

plugins/obs-ffmpeg/texture-amf.cpp

@@ -964,7 +964,7 @@ static obs_properties_t *amf_properties_internal(bool hevc)
 	obs_property_set_modified_callback(p, rate_control_modified);
 
 	p = obs_properties_add_int(props, "bitrate", obs_module_text("Bitrate"),
-				   50, 300000, 50);
+				   50, 100000, 50);
 	obs_property_int_set_suffix(p, " Kbps");
 
 	obs_properties_add_int(props, "cqp", obs_module_text("NVENC.CQLevel"),