accel/qaic: Fix integer overflow in qaic_validate_req()

These are u64 variables that come from the user via
qaic_attach_slice_bo_ioctl().  Use check_add_overflow() to ensure that
the math doesn't have an integer wrapping bug.

Cc: stable@vger.kernel.org
Fixes: ff13be83 ("accel/qaic: Add datapath")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Signed-off-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/176388fa-40fe-4cb4-9aeb-2c91c22130bd@stanley.mountain