boards: amlogic: Fix boards README

Fix typos and update the supported devices for all Amlogic boards.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/board/amlogic/odroid-c2/README b/board/amlogic/odroid-c2/README
index b407c04..bed48c5 100644
--- a/board/amlogic/odroid-c2/README
+++ b/board/amlogic/odroid-c2/README
@@ -20,6 +20,11 @@
  - serial
  - eMMC, microSD
  - Ethernet
+ - I2C
+ - Regulators
+ - Reset controller
+ - Clock controller
+ - ADC
 
 u-boot compilation
 ==================