ARM: sirf: mark sirfsoc_init_late as __maybe_unused

sirfsoc_init_late is called by each of the three individual
SoC definitions, but in a randconfig build, we can encounter
a situation where they are all disabled:

arch/arm/mach-prima2/common.c:18:123: warning: 'sirfsoc_init_late' defined but not used [-Wunused-function]

While that is not a useful configuration, the warning also
doesn't help, so this patch marks the function as __maybe_unused
to let the compiler know it is there intentionally.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-prima2/common.c

@@ -15,7 +15,7 @@
 #include <linux/of_platform.h>
 #include "common.h"
 
-static void __init sirfsoc_init_late(void)
+static void __init __maybe_unused sirfsoc_init_late(void)
 {
 	sirfsoc_pm_init();
 }