Force the SMD regulator driver to be compiled-in

Force the SMD regulator driver to be compiled-in

BugLink: http://bugs.launchpad.net/bugs/1763040
Allowing REGULATOR_QCOM_SMD_RPM to be a module requires solving exporting
some symbols and fixing some dependencies. Since this driver is due to be
refactored, let's take a shortcut to simply disallow modules for now.

Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
(cherry picked from commit ebe10495a722f38cd4f4cfb124e0dc301f01e54b
http://git.linaro.org/landing-teams/working/qualcomm/kernel.git release/qcomlt-4.14)
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>