overflow: Use POD in check_shl_overflow()

The check_shl_overflow() uses u64 type that is defined in types.h.
Instead of including that header, just switch to use POD type
directly.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20240228204919.3680786-2-andriy.shevchenko@linux.intel.com


Signed-off-by: Kees Cook <keescook@chromium.org>