clk: remove tango4 driver

The tango platform is getting removed, so the driver is no
longer needed.

Cc: Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc: Mans Rullgard <mans@mansr.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210120131026.1721788-2-arnd@kernel.org
Acked-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: arndb

Documentation/devicetree/bindings/clock/tango4-clock.txt

@@ -62,7 +62,6 @@ obj-$(CONFIG_COMMON_CLK_SI570)		+= clk-si570.o
 obj-$(CONFIG_COMMON_CLK_STM32F)		+= clk-stm32f4.o
 obj-$(CONFIG_COMMON_CLK_STM32H7)	+= clk-stm32h7.o
 obj-$(CONFIG_COMMON_CLK_STM32MP157)	+= clk-stm32mp1.o
-obj-$(CONFIG_ARCH_TANGO)		+= clk-tango4.o
 obj-$(CONFIG_CLK_TWL6040)		+= clk-twl6040.o
 obj-$(CONFIG_ARCH_U300)			+= clk-u300.o
 obj-$(CONFIG_ARCH_VT8500)		+= clk-vt8500.o