riscv: Fix sparse warning about different address spaces

riscv: Fix sparse warning about different address spaces

We did not propagate the __user attribute of the pointers in
__get_kernel_nofault() and __put_kernel_nofault(), which results in
sparse complaining:

>> mm/maccess.c:41:17: sparse: sparse: incorrect type in argument 2 (different address spaces) @@     expected void const [noderef] __user *from @@     got unsigned long long [usertype] * @@
   mm/maccess.c:41:17: sparse:     expected void const [noderef] __user *from
   mm/maccess.c:41:17: sparse:     got unsigned long long [usertype] *

So fix this by correctly casting those pointers.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202508161713.RWu30Lv1-lkp@intel.com/
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Fixes: f6bff7827a48 ("riscv: uaccess: use 'asm_goto_output' for get_user()")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Cyril Bur <cyrilbur@tenstorrent.com>
Link: https://lore.kernel.org/r/20250903-dev-alex-sparse_warnings_v1-v1-2-7e6350beb700@rivosinc.com
Signed-off-by: Paul Walmsley <pjw@kernel.org>