The Nucleo STM32F413 board is missing the default pinmux for PWM2 on
PA0, as stated in the doc. The same pinmux is also done for other
similar Nucleo board. So add it!
Change-Id: I2086c0a4ce65d68455a0978570f118e965f4c6ca
Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>