clk: mmp: Remove old non-OF clock drivers

There are no MMP2, PXA168 or PXA910 boards still using board files which
would use these drivers, so remove them.

Signed-off-by: Duje Mihanović <duje.mihanovic@skole.hr>
Link: https://lore.kernel.org/r/20230804-drop-old-mmp-clk-v1-1-0c07db6cee90@skole.hr
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Author: LegoLivesMatter

drivers/clk/mmp/Makefile

@@ -11,8 +11,4 @@ obj-$(CONFIG_MACH_MMP_DT) += clk-of-pxa168.o clk-of-pxa910.o
 obj-$(CONFIG_COMMON_CLK_MMP2) += clk-of-mmp2.o clk-pll.o pwr-island.o
 obj-$(CONFIG_COMMON_CLK_MMP2_AUDIO) += clk-audio.o
 
-obj-$(CONFIG_CPU_PXA168) += clk-pxa168.o
-obj-$(CONFIG_CPU_PXA910) += clk-pxa910.o
-obj-$(CONFIG_CPU_MMP2) += clk-mmp2.o
-
 obj-y += clk-of-pxa1928.o