device-tree-gpio-naming: Order sections alphabetically

Change-Id: I3066ace0db0222ac9e6c3adc09e50540b2ad4784
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/designs/device-tree-gpio-naming.md b/designs/device-tree-gpio-naming.md
index 845fc8a..5c78a4d 100644
--- a/designs/device-tree-gpio-naming.md
+++ b/designs/device-tree-gpio-naming.md
@@ -47,6 +47,11 @@
 system which provides one of the below GPIOs must name it as listed in
 this document. This document must be updated as new common GPIOs are added.
 
+### Buttons
+Pattern: `*-button`
+
+#### power-button
+
 ### LEDs
 Pattern: `led-*`
 
@@ -86,11 +91,6 @@
 condition is present. The status will reflect a standby regulator power faulted
 condition when an unexpected drop in standby power is detected.
 
-### Buttons
-Pattern: `*-button`
-
-#### power-button
-
 ### Presence
 Pattern: `presence-*`