Using GPIOA_IDR directly looks a bit arcane, and the example can benefit
from introducing gpio_get() and how to use it. The stm32f0-discovery
example already does it like this.
Correctly migrate stm32f103_usb_driver to st_usbfs_v1_driver instead of the
f107 driver.
Fixes: 976720c355
Reviewed-by: Karl Palsson <karlp@tweak.net.au>
Be specifically careful with the usb examples. There is likely some
breakage to be expected, not sure I updated all the drivers to the
correct types for the respective chips.
