Servo motion scale

**Describe the bug**
Full scale servo motions are only a few degrees.

**To Reproduce**
Alter rc_pru_start to point PRU1 at remoteproc1.
Use rc_test_servos or custom example to command servo through range of motion from +90 to -90 degrees.
Resulting motion is only some 10ish degrees. Direction seems correct, but scale is really short.

**Expected behavior**
Expected servo to move through full +/-90 degree range.

**background**
I'm using an older Futaba FP-S148 servo with range from 550 us to 2350 us. When using these min and max on a RPi with hardware pwm, the servo moves the full expected range of +/-90 degrees.
I can't measure the waveforms produced by the Blue.

**Platform information**
rc_test_drivers

Kernel: 4.19.94-ti-r42
BeagleBoard.org Debian Buster IoT Image 2020-04-06
Debian: 10.3

PASSED: gpio 0
PASSED: gpio 1
PASSED: gpio 2
PASSED: gpio 3
PASSED: pwm0
PASSED: pwm1
PASSED: pwm2
PASSED: eqep0
PASSED: eqep1
PASSED: eqep2
PASSED: pru-rproc
PASSED: uart1
PASSED: uart2
PASSED: uart4
PASSED: uart5
PASSED: i2c1
PASSED: i2c2
PASSED: spi
PASSED: LED
PASSED: ADC iio

Currently running on a:
MODEL_BB_BLUE
Robot Control library Version:
1.0.4
I don't know what clock the PRU uses, but the Blue was in performance governor mode and scaling_cur_freq = 1000000.