ARM: uniphier: remove sLD3 SoC support

arch/arm/dts/Makefile

arch/arm/dts/uniphier-sld3-ref.dts

arch/arm/dts/uniphier-sld3.dtsi

arch/arm/mach-uniphier/Kconfig

arch/arm/mach-uniphier/arm32/cache-uniphier.c

arch/arm/mach-uniphier/arm32/debug_ll.S

arch/arm/mach-uniphier/arm32/lowlevel_init.S

arch/arm/mach-uniphier/arm32/psci.c

arch/arm/mach-uniphier/bcu/Makefile

arch/arm/mach-uniphier/bcu/bcu-sld3.c

arch/arm/mach-uniphier/board_init.c

arch/arm/mach-uniphier/boards.c

arch/arm/mach-uniphier/boot-device/Makefile

arch/arm/mach-uniphier/boot-device/boot-device-sld3.c

arch/arm/mach-uniphier/boot-device/boot-device.c

arch/arm/mach-uniphier/boot-device/boot-device.h

arch/arm/mach-uniphier/clk/Makefile

arch/arm/mach-uniphier/clk/clk-dram-ld4.c

arch/arm/mach-uniphier/clk/clk-early-ld4.c

arch/arm/mach-uniphier/clk/dpll-sld3.c