lib: Remove umoddi3 and udivmoddi4

These were only necessary for an out-of-tree driver that has since been
fixed to use the proper divide routines.  I've simply reverted the pair
of commits we made last week.

Signed-off-by: Palmer Dabbelt <palmer@sifive.com>

arch/riscv/Kconfig

@@ -109,7 +109,6 @@ config ARCH_RV32I
 	select GENERIC_LIB_ASHRDI3
 	select GENERIC_LIB_LSHRDI3
 	select GENERIC_LIB_UCMPDI2
-	select GENERIC_LIB_UMODDI3
 
 config ARCH_RV64I
 	bool "RV64I"