clk: remove zte zx driver

The zte zx platform is getting removed, so this driver is no
longer needed.

Cc: Jun Nie <jun.nie@linaro.org>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210120131026.1721788-3-arnd@kernel.org
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: arndb

Documentation/devicetree/bindings/clock/zx296702-clk.txt

@@ -120,6 +120,5 @@ obj-y					+= versatile/
 ifeq ($(CONFIG_COMMON_CLK), y)
 obj-$(CONFIG_X86)			+= x86/
 endif
-obj-$(CONFIG_ARCH_ZX)			+= zte/
 obj-$(CONFIG_ARCH_ZYNQ)			+= zynq/
 obj-$(CONFIG_COMMON_CLK_ZYNQMP)         += zynqmp/