[PATCH] iommufd/selftest: print size_t with %zu

[Sasha Levin]

On 32-bit architectures size_t is an unsigned int, and printing it with
%lu warns:

  iommufd.c:2157:30: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t' {aka 'unsigned int'} [-Wformat=]

Use %zu.

Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
Found with a 32-bit build of the selftests with a 64-bit time_t (gcc 16
and clang 21 with -m32 -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64);
KernelCI's 32-bit arm builds show the same warnings. The changed files
build without format warnings there now, and the x86_64 builds don't
change. The other selftests get the same kind of fix in separate
patches.

 tools/testing/selftests/iommu/iommufd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/iommu/iommufd.c b/tools/testing/selftests/iommu/iommufd.c
index ca2b35e9d443a..c4d4f3659626e 100644
--- a/tools/testing/selftests/iommu/iommufd.c
+++ b/tools/testing/selftests/iommu/iommufd.c
@@ -2154,7 +2154,7 @@ FIXTURE_SETUP(iommufd_dirty_tracking)
 
 	rc = posix_memalign(&self->buffer, HUGEPAGE_SIZE, mmap_buffer_size);
 	if (rc || !self->buffer) {
-		SKIP(return, "Skipping buffer_size=%lu due to errno=%d",
+		SKIP(return, "Skipping buffer_size=%zu due to errno=%d",
 			   mmap_buffer_size, rc);
 	}
 	assert((uintptr_t)self->buffer % HUGEPAGE_SIZE == 0);
-- 
2.53.0