selftests: vDSO: vdso_test_abi: Use UAPI system call numbers

selftests: vDSO: vdso_test_abi: Use UAPI system call numbers

SYS_clock_getres might have been redirected by libc to some other system
call than the actual clock_getres. For testing it is required to use
exactly this system call.

Use the system call number exported by the UAPI headers which is always
correct.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20251223-vdso-compat-time32-v1-3-97ea7a06a543@linutronix.de