vsock/test: fix parameter types in SO_VM_SOCKETS_* calls

Change parameters of SO_VM_SOCKETS_* to unsigned long long as documented
in the vm_sockets.h, because the corresponding kernel code requires them
to be at least 64-bit, no matter what architecture. Otherwise they are
too small on 32-bit machines.

Fixes: 5c338112 ("test/vsock: rework message bounds test")
Fixes: 685a21c3 ("test/vsock: add big message test")
Fixes: 542e893f ("vsock/test: two tests to check credit update logic")
Fixes: 8abbffd2 ("test/vsock: vsock_perf utility")
Signed-off-by: Konstantin Shkolnyy <kshk@linux.ibm.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>