Add documentation for common device error

Prior commit added xyz.openbmc_project.Common.Device.ReadFailure
and xyz.openbmc_project.Common.Device.WriteFailure but did not
have enough documentation.

This commit adds documentation on how to interpret that error

Change-Id: I627b44ba7d4e3d0adc9f2b7362afbe470d8467bc
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/xyz/openbmc_project/Common/Device.errors.yaml b/xyz/openbmc_project/Common/Device.errors.yaml
index 429762d..3495de3 100644
--- a/xyz/openbmc_project/Common/Device.errors.yaml
+++ b/xyz/openbmc_project/Common/Device.errors.yaml
@@ -1,7 +1,19 @@
 # xyz.openbmc_project.Common.Device.ReadFailure
 - name: ReadFailure
   description: Failed to read from the device.
+               This can be used by any application that
+               gets a failure reading from a device.
+               It is up to the implementation on how to
+               react to this error based on the use-case.
+               Refer to the interface specification that
+               references this for additional information.
 
 # xyz.openbmc_project.Common.Device.WriteFailure
 - name: WriteFailure
   description: Failed to write to device.
+               This can be used by any application that
+               gets a failure writing to a device.
+               It is up to the implementation on how to
+               react to this error based on the use-case.
+               Refer to the interface specification that
+               references this for additional information.