arch/non-x86: Flip HAVE_MONOTONIC_TIMER default

Also remove allwinner/a10 dummy monotonic_timer
implementation.

Change-Id: I9dfa9b92dc63375465e3bb87b73eeefad601c810
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34112
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/soc/sifive/fu540/Kconfig

@@ -22,8 +22,6 @@ config SOC_SIFIVE_FU540
 	select ARCH_ROMSTAGE_RISCV
 	select ARCH_RAMSTAGE_RISCV
 	select DRIVERS_UART_SIFIVE
-	select GENERIC_UDELAY
-	select HAVE_MONOTONIC_TIMER
 	select RISCV_USE_ARCH_TIMER
 	select UART_OVERRIDE_REFCLK