readme: update prerequisites

Signed-off-by: Sanjay Singh Rawat <sanjay.rawat@linaro.org>
diff --git a/README b/README
index 3bf1659..1479db1 100644
--- a/README
+++ b/README
@@ -14,3 +14,11 @@
 And when gpio direction is "out", use 'V' key to change gpio value.
 
  -- Shaojie Sun <shaojie.sun@linaro.org> Mon, 29 Jul 2013
+
+Prerequistes
+------------
+- Kernel should have support enabled for:
+  - DEBUG_FS
+  - GPIO_SYSFS
+  - HWMON
+  - REGULATOR