clk: remove u300 driver

The ST-Ericsson U300 platform is getting removed, so this driver is no
longer needed.

Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20210120131026.1721788-5-arnd@kernel.org
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: arndb

Documentation/devicetree/bindings/clock/ste-u300-syscon-clock.txt

@@ -63,7 +63,6 @@ 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_CLK_TWL6040)		+= clk-twl6040.o
-obj-$(CONFIG_ARCH_U300)			+= clk-u300.o
 obj-$(CONFIG_ARCH_VT8500)		+= clk-vt8500.o
 obj-$(CONFIG_COMMON_CLK_VC5)		+= clk-versaclock5.o
 obj-$(CONFIG_COMMON_CLK_WM831X)		+= clk-wm831x.o