greybus: es2: comment out unused functions

The Qualcomm kernel builds with -Werror so the existing es2.c driver
breaks the build due to unused static functions.  As we are still
hashing out exactly how to implement this logic at the moment, just
comment out the functions to make the build be clean, no logic changes
happen here at all.

Reported-by: Michael Scott <michael.scott@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>