In the Matlab Arduino package there is the file:
c:\ProgramData\MATLAB\SupportPackages\R2017a\toolbox\matlab\hardware\supportpackages\arduinoio\src\ArduinoServer.ino
Modify it setup() function:
void setup()
{ MWArduino.begin([connection_type]);
TCCR1A = TCCR1A & 0xe0 | 1;
TCCR1B = TCCR1B & 0xe0 | 0x09;
}