RDMA/siw: Pass a pointer to virt_to_page()

RDMA/siw: Pass a pointer to virt_to_page()

Functions that work on a pointer to virtual memory such as
virt_to_pfn() and users of that function such as
virt_to_page() are supposed to pass a pointer to virtual
memory, ideally a (void *) or other pointer. However since
many architectures implement virt_to_pfn() as a macro,
this function becomes polymorphic and accepts both a
(unsigned long) and a (void *).

If we instead implement a proper virt_to_pfn(void *addr)
function the following happens (occurred on arch/arm):

drivers/infiniband/sw/siw/siw_qp_tx.c:32:23: warning: incompatible
  integer to pointer conversion passing 'dma_addr_t' (aka 'unsigned int')
  to parameter of type 'const void *' [-Wint-conversion]
drivers/infiniband/sw/siw/siw_qp_tx.c:32:37: warning: passing argument
  1 of 'virt_to_pfn' makes pointer from integer without a cast
  [-Wint-conversion]
drivers/infiniband/sw/siw/siw_qp_tx.c:538:36: warning: incompatible
  integer to pointer conversion passing 'unsigned long long'
  to parameter of type 'const void *' [-Wint-conversion]

Fix this with an explicit cast. In one case where the SIW
SGE uses an unaligned u64 we need a double cast modifying the
virtual address (va) to a platform-specific uintptr_t before
casting to a (void *).

Fixes: fac165e35a96 ("rdma/siw: transmit path")
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220902215918.603761-1-linus.walleij@linaro.org
Signed-off-by: Leon Romanovsky <leon@kernel.org>