No, your diagram is correct. A P channel MOSFET would not work with a positive supply.
So the MOSFET in your diagram must be an N channel.
I don't see the need for a resistor from the gate to gnd. If the "chip is off" as he said (I assume he means the PIC) then its outputs should be at gnd potential and so the MOSFET will be off.
I would leave the diode across the motor to suppress spikes. If you only rely on the internal diode, the spike current will have to go through the supply also.
Len