EXTI - Remove boolean argument from EXTIEnable.

It's confusing to have a method called EXTIEnable that takes an argument
that can DISABLE the line.

There are usually 3 options for this:
1. Use two methods, one for enable, one for disable.
2. Use enum constants instead of the boolean argument.
3. Rename to '*Set', e.g. EXTISet(...)

This commit applies option 1 above, as it's cleaner and the most common
use case in the codebase.

src/test/unit/baro_bmp388_unittest.cc

@@ -180,7 +180,9 @@ void EXTIHandlerInit(extiCallbackRec_t *, extiHandlerCallback *) {
 void EXTIConfig(IO_t, extiCallbackRec_t *, int, ioConfig_t, extiTrigger_t) {
 }
 
-void EXTIEnable(IO_t, bool) {
+void EXTIEnable(IO_t) {
+}
+void EXTIDisable(IO_t) {
 }