clk: x86: Change name from ST to FCH

AMD SoC general pupose clk is present in new platforms with
minor differences. We can reuse the same clk driver for other
platforms. Hence, changing name from ST(SoC) to FCH(IP)

Signed-off-by: Akshu Agrawal <akshu.agrawal@amd.com>
Reviewed-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>