msm: apq8064: remove device registration of touchscreen FET on MTP

This power FET does not exist on apq8064 MTP and registration of
its platform device conflicts with usage of pmic gpio-23 for other
purposes on the MTP target.

Change-Id: I37d679ea9d984579ebb27d3acd6002d4d579c9b4
Signed-off-by: Joel King <joelking@codeaurora.org>