powerpc/rtas-rtc: remove unused constant

RTAS_CLOCK_BUSY is unused, remove it.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210503175811.1528208-1-nathanl@linux.ibm.com

arch/powerpc/kernel/rtas-rtc.c

@@ -12,7 +12,7 @@
 
 
 #define MAX_RTC_WAIT 5000	/* 5 sec */
-#define RTAS_CLOCK_BUSY (-2)
+
 time64_t __init rtas_get_boot_time(void)
 {
 	int ret[8];