ARM: DRA7XX/AM43XX: randconfig fixes

DRA7XX and AM43XX were missing common clock code from the Makefile, which
causes build breakage in DRA7XX / AM43XX only builds once clock support
for these SoCs is added. Add the missing entries to the Makefile as
preparation of this.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>