clocksource: clint: Export clint_time_val for modules

clint_time_val will soon be used by the RISC-V implementation of
random_get_entropy(), which is a static inline function that may be used by
modules (at least CRYPTO_JITTERENTROPY=m).
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NPalmer Dabbelt <palmerdabbelt@google.com>

drivers/clocksource/timer-clint.c

@@ -38,6 +38,7 @@ static unsigned int clint_timer_irq;
 
 #ifdef CONFIG_RISCV_M_MODE
 u64 __iomem *clint_time_val;
+EXPORT_SYMBOL(clint_time_val);
 #endif
 
 static void clint_send_ipi(const struct cpumask *target)