clk: ti: Tighten some TI clock driver dependencies

clk: ti: Tighten some TI clock driver dependencies

Attempting to build with "allyesconfig" means that we try and build all
available options for the sandbox platforms. Doing so exposes that the
drivers under drivers/clk/ti/ can only be compiled or linked on
ARCH_OMAP2PLUS platforms as some drivers require platform specific
headers while other drivers depend on these first drivers to link.
Express those requirements in Kconfig as well.

Reviewed-by: Manorit Chawdhry <m-chawdhry@ti.com>
Signed-off-by: Tom Rini <trini@konsulko.com>