dma-mapping: fix tracing dma_alloc/free with vmalloc'd memory

Not all virtual addresses have physical addresses, such as if they were
vmalloc'd. Just trace the virtual address instead of trying to trace a
physical address. This aligns with the API, and is good enough to
associate dma_alloc with dma_free.

Fixes: 038eb433 ("dma-mapping: add tracing for dma-mapping API calls")
Reported-by:  <syzbot+b4bfacdec173efaa8567@syzkaller.appspotmail.com>
Closes: https://lore.kernel.org/all/670ebde5.050a0220.d9b66.0154.GAE@google.com/


Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Signed-off-by: Christoph Hellwig <hch@lst.de>