ARM: ep93xx: fix missing-prototype warnings

ep93xx_clocksource_read() is only called from the file it is declared in,
while ep93xx_timer_init() is declared in a header that is not included here.

arch/arm/mach-ep93xx/timer-ep93xx.c:120:13: error: no previous prototype for 'ep93xx_timer_init'
arch/arm/mach-ep93xx/timer-ep93xx.c:63:5: error: no previous prototype for 'ep93xx_clocksource_read'

Fixes: 000bc178 ("ARM: ep93xx: switch to GENERIC_CLOCKEVENTS")
Acked-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Link: https://lore.kernel.org/r/20230516153109.514251-3-arnd@kernel.orgSigned-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-ep93xx/timer-ep93xx.c

@@ -9,6 +9,7 @@
 #include <linux/io.h>
 #include <asm/mach/time.h>
 #include "soc.h"
+#include "platform.h"
 
 /*************************************************************************
  * Timer handling for EP93xx
@@ -60,7 +61,7 @@ static u64 notrace ep93xx_read_sched_clock(void)
 	return ret;
 }
 
-u64 ep93xx_clocksource_read(struct clocksource *c)
+static u64 ep93xx_clocksource_read(struct clocksource *c)
 {
 	u64 ret;