clk: zynqmp: Enable the driver if ZYNQMP_FIRMWARE is selected

clk: zynqmp: Enable the driver if ZYNQMP_FIRMWARE is selected

When booting the kernel on zynqmp based platforms such as Ultra96v2,
peripheral drivers such as that for the sdcard depend on the presence
of clocks.

Enable the clock driver if it's dependencies are compiled to avoid
building an unbootable kernel.

Signed-off-by: Punit Agrawal <punit1.agrawal@toshiba.co.jp>
Link: https://lore.kernel.org/r/20210322061754.1065367-2-punit1.agrawal@toshiba.co.jp
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>