remoteproc/omap: fix randconfig unmet direct dependencies

OMAP_REMOTEPROC selects REMOTEPROC and RPMSG, both of which depend
on EXPERIMENTAL, so let's have OMAP_REMOTEPROC depend on EXPERIMENTAL
too, in order to avoid the below randconfig warnings.

warning: (OMAP_REMOTEPROC) selects REMOTEPROC which has unmet direct dependencies (EXPERIMENTAL)
warning: (OMAP_REMOTEPROC) selects RPMSG which has unmet direct dependencies (EXPERIMENTAL)

Cc: stable <stable@vger.kernel.org>
Reported-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>