tvservice: Increase max callback count to 5
tvservice: Increase max callback count to 5

A maximum callback count of 2 might be too low for some usecases.

Signed-off-by: Julian Scheel <354106e416911844661e1603d99ecf7d1c318dda@jusst.de>

popcornmix/userland,FIIT-TNL/userland,maxnet/userland,fredericofs/userland,6by9/userland,gonzoua/userland,salih/userland,roberttidey/userland,maxnet/userland,6by9/userland,oniongarlic/userland,gonzoua/userland,DexterInd/userland,popcornmix/userland,luked99/userland-1,popcornmix/userland,StealthMicro/userland,salih/userland,maroviher/userland,yzhahn/userland,luked99/userland-1,oniongarlic/userland,DexterInd/userland,FIIT-TNL/userland,FIIT-TNL/userland,roberttidey/userland,hyunkim9123/userland,kraj/userland,JamesH65/userland,fredericofs/userland,raspberrypi/userland,d3faultdotxbe/raspivid-accurate-fps-via-hacky-framedropping,raspberrypi/userland,maxnet/userland,ethanol100/userland,hyunkim9123/userland,adamheinrich/userland,JamesH65/userland,kraj/userland,roberttidey/userland,raspberrypi/userland,fredericofs/userland,erlerobot/rpi-userland,StealthMicro/userland,oniongarlic/userland,DexterInd/userland,d3faultdotxbe/raspivid-accurate-fps-via-hacky-framedropping,salih/userland,adamheinrich/userland,JamesH65/userland,erlerobot/rpi-userland,maroviher/userland,kraj/userland,erlerobot/rpi-userland,gonzoua/userland,d3faultdotxbe/raspivid-accurate-fps-via-hacky-framedropping,ethanol100/userland,hyunkim9123/userland,luked99/userland-1,adamheinrich/userland,StealthMicro/userland,yzhahn/userland,ethanol100/userland,d3faultdotxbe/raspivid-accurate-fps-via-hacky-framedropping,yzhahn/userland,6by9/userland,maroviher/userland