riscv: process: use unsigned int instead of unsigned long for put_user()

riscv: process: use unsigned int instead of unsigned long for put_user()

The specification of prctl() for GET_UNALIGN_CTL states that the value is
returned in an unsigned int * address passed as an unsigned long. Change
the type to match that and avoid an unaligned access as well.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20250602193918.868962-3-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@dabbelt.com>