slippy/falco/peppy: make GPIO interrupts be edge triggered

The drivers are designed to work with an edge triggered interrupt.

Change-Id: I35a121ecfb6409bb9049f4d1e034185bb3bb7557
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/61664
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/4360
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
3 files changed