Change CPU_GPIO_DisablePin AltFunction parameter type to UINT32

[cw2]

As I have hit similar issue with the GPIO API, I vote for @smaillet-ms suggestion in #464 (comment) to change the type of the alternate parameter in CPU_GPIO_DisablePin function from GPIO_ALT_MODE to UINT32, and add inline function for backward compatibility:

void CPU_GPIO_DisablePin(GPIO_PIN Pin, GPIO_RESISTOR ResistorState, UINT32 Direction, UINT32 AltFunction);

inline void CPU_GPIO_DisablePin(GPIO_PIN Pin, GPIO_RESISTOR ResistorState, UINT32 Direction, GPIO_ALT_MODE AltFunction)
{
  return CPU_GPIO_DisablePin(Pin, ResistorState, Direction, (UINT32)AltFunction);
}

[smaillet-ms]

Well, that's even simpler than the idea of using a strongly typed enum - works for me! Send a PR, but we'll need to get the build succeeding on all platforms before it can be merged in. (At this point in time The GCC builds for MCBSTM32F400 are failing).

[cw2]

Does that work in Keil? I am not sure which version supports [C++11] strongly typed enums.

Specifying the underlying type (enum A : xxx) results in Error: #70: incomplete type is not allowed.

[smaillet-ms]

It requires some compiler settings so is more work to get functional in NETMF. The solution posted here skips all that rather nicely so I wouldn't bother with the strongly typed enum.

[cw2]

Oh, I misread your previous comment, sorry. I'll have a look at what's wrong with GCC for MCBSTM solution (so I don't have broken build in PR : )...