packages: add PSE (PoE) packages

packages: add PSE (PoE) packages

There are a number of pse chips already present in upstream Linux.
OpenWrt is starting to support a number of devices can contain various pse
chips.  But having all the pse chip combinations defined at the target
level will result in bloat on images.
Present the current upstream Linux pse drivers as packages so that they
can be selectively included per board (rather than per target).

Signed-off-by: Bevan Weiss <bevan.weiss@gmail.com>
[Make it depend on REGULATOR_SUPPORT, and !SMALL_FLASH]
Link: https://github.com/openwrt/openwrt/pull/22172
Signed-off-by: Robert Marko <robimarko@gmail.com>