RDMA/erdma: Use vcalloc() instead of vzalloc()

RDMA/erdma: Use vcalloc() instead of vzalloc()

Replace vzalloc() with vcalloc() in vmalloc_to_dma_addrs().  As noted in
the kernel documentation [1], open-coded multiplication in allocator
arguments is discouraged because it can lead to integer overflow.

Use vcalloc() to gain built-in overflow protection, making memory
allocation safer when calculating allocation size compared to explicit
multiplication.

[1]: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments

Link: https://patch.msgid.link/r/20250821072209.510348-1-rongqianfeng@vivo.com
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Reviewed-by: Cheng Xu <chengyou@linux.alibaba.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>