tests/pwm: enable PWM case to work on D2000 board

This test case uses PWM0 port to test PWM on Quark Se.
However PWM0 port on Quark D2000 is initialized as tdo,
not PWM0 and disabling tdo will kill JTAG on D2000. So
use PWM1 and add PINMUX setting code to configure PIN_24
as PWM1 port, then the case will work on D2000 board.

Change-Id: Ib28d4750dac7396529388b781fb64bde048139d6
Signed-off-by: Qiu Peiyang <peiyangx.qiu@intel.com>