kernel: Change the prototype of k_thread_access_grant.

This API was using variable number of arguments. Which is not
allowed according to misra c guidelines(Rule 17.1). Hence making
this API into a macro and using the util macro FOR_EACH_FIXED_ARG
to get the same functionality.

There is one deviation from the old function. The last argument
shouldn't be NULL.

Signed-off-by: Adithya Baglody <adithya.nagaraj.baglody@intel.com>