xsk: add missing virtual address conversion for page

In commit 7ead4405 ("xsk: convert xdp_copy_frags_from_zc() to use
page_pool_dev_alloc()"), when converting from netmem to page, I missed a
call to page_address() around skb_frag_page(frag) to get the virtual
address of the page. This commit uses skb_frag_address() helper to fix
the issue.

Fixes: 7ead4405 ("xsk: convert xdp_copy_frags_from_zc() to use page_pool_dev_alloc()")
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Link: https://patch.msgid.link/20250522040115.5057-1-minhquangbui99@gmail.com


Signed-off-by: Paolo Abeni <pabeni@redhat.com>