apalis/colibri_t30: add comment about tristate and input vs. output pinmuxing

Add pinmuxing comment stating that TRISTATE means the output driver is
tri-stated and INPUT means the input driver is enabled vs. OUTPUT where
it is disabled.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>
diff --git a/board/toradex/apalis_t30/pinmux-config-apalis_t30.h b/board/toradex/apalis_t30/pinmux-config-apalis_t30.h
index 49c2df7..8d6696a 100644
--- a/board/toradex/apalis_t30/pinmux-config-apalis_t30.h
+++ b/board/toradex/apalis_t30/pinmux-config-apalis_t30.h
@@ -11,7 +11,9 @@
 		.pingrp		= PMUX_PINGRP_##_pingrp,	\
 		.func		= PMUX_FUNC_##_mux,		\
 		.pull		= PMUX_PULL_##_pull,		\
+/* TRISTATE here means output driver is tri-stated */ \
 		.tristate	= PMUX_TRI_##_tri,		\
+/* INPUT here means input driver is enabled vs. OUTPUT where it is disabled */ \
 		.io		= PMUX_PIN_##_io,		\
 		.lock		= PMUX_PIN_LOCK_DEFAULT,	\
 		.od		= PMUX_PIN_OD_DEFAULT,		\