swiotlb: Enrich message about buffer overflow

When buffer overflow is detected in swiotlb_bounce(), the following
error is printed:

 nvme 0000:00:0a.0: Buffer overflow detected. Allocation size: 4096. Mapping size: 8192.
 WARNING: CPU: 25 PID: 657 at kernel/dma/swiotlb.c:889 swiotlb_bounce+0x22b/0x360

This error is not enough to reliable determine the original allocated slot size as
printed value depends on TLB offset too, so add it to the print:

 nvme 0000:00:0a.0: Buffer overflow detected. Allocation size: 4096. Mapping size: 8192. TLB offset: 0
 WARNING: CPU: 60 PID: 660 at kernel/dma/swiotlb.c:889 swiotlb_bounce+0x234/0x380

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>