selftests: vDSO: vdso_test_correctness: Handle different tv_usec types

selftests: vDSO: vdso_test_correctness: Handle different tv_usec types

On SPARC the field tv_usec of 'struct timespec' is not a 'long int', but
only a regular int. In this case the format string is incorrect and will
trigger compiler warnings.

Avoid the warnings by casting to 'long long', similar to how it is done for
the tv_sec and what the other similar selftests are doing.

Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Link: https://patch.msgid.link/20260227-vdso-selftest-cleanups-v2-4-d84830fa8beb@linutronix.de