fix(pl18): USB detect pin can be uninitialized in bootloader

[richardclli]

When work on some further development, discovered that the USB detection pin in PL18/PL18EV can be uninitialized in bootloader mode, this can cause potential problem.

[mha1]

shouldn't you do something like this to avoid stack garbage on potentially unused struct members?

GPIO_InitTypeDef GPIO_InitStruct = {0};

[richardclli]

No need:

1. All members are already covered in this code
2. This is only a quick fix for transition, next version will change to LL library.

shouldn't you do something like this to avoid stack garbage on potentially unused struct members?

GPIO_InitTypeDef GPIO_InitStruct = {0};