clocksource/drivers/riscv: Make RISCV_TIMER depends on RISCV_SBI

The riscv timer is set via SBI timer call, let's make RISCV_TIMER
depends on RISCV_SBI, and it also fixes some build issue.

Fixes: d5be89a8d118 ("RISC-V: Resurrect the MMIO timer implementation for M-mode systems")
Signed-off-by: Kefeng Wang <[e-mail]>
Reviewed-by: Palmer Dabbelt <[e-mail]>
Acked-by: Palmer Dabbelt <[e-mail]>
Signed-off-by: Daniel Lezcano <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/clocksource/Kconfig

···
 
 config RISCV_TIMER
 	bool "Timer for the RISC-V platform" if COMPILE_TEST
-	depends on GENERIC_SCHED_CLOCK && RISCV
+	depends on GENERIC_SCHED_CLOCK && RISCV && RISCV_SBI
 	select TIMER_PROBE
 	select TIMER_OF
 	help