KVM: selftests: Use s32 instead of int32_t

KVM: selftests: Use s32 instead of int32_t

Use s32 instead of int32_t to make the KVM selftests code more concise
and more similar to the kernel (since selftests are primarily developed
by kernel developers).

This commit was generated with the following command:

  git ls-files tools/testing/selftests/kvm | xargs sed -i 's/int32_t/s32/g'

Then by manually adjusting whitespace to make checkpatch.pl happy.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://patch.msgid.link/20260420212004.3938325-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>