selftests: vDSO: vdso_test_getrandom: Drop unused include of linux/compiler.h

The header is unused. Furthermore this is not a real UAPI header,
but only exists in tools/include/.
This prevents building the selftest against real UAPI headers.

Drop the include.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250611-selftests-vdso-fixes-v3-3-e62e37a6bcf5@linutronix.de

Author: t-8ch

tools/testing/selftests/vDSO/vdso_test_getrandom.c

@@ -21,7 +21,6 @@
 #include <sys/wait.h>
 #include <sys/types.h>
 #include <linux/random.h>
-#include <linux/compiler.h>
 #include <linux/ptrace.h>
 
 #include "../kselftest.h"