regulator: core: Only support passing enable GPIO descriptors

regulator: core: Only support passing enable GPIO descriptors

Now that we changed all providers to pass descriptors into the core
for enable GPIOs instead of a global GPIO number, delete the support
for passing GPIO numbers in, and we get a cleanup and size reduction
in the core, and from a GPIO point of view we use the modern, cleaner
interface.

Tested-by: Marek Szyprowski <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Signed-off-by: Mark Brown <[email protected]>