Split out type and function definitions for a cleaner separation for
some consumers of these functions. Concretely, nr_mac_common.h includes
various ASN.1 NR RRC headers, but not all consumers of these APIs might
need these headers. For instance, the next commit will use these
functions in the driver for 7.2 (it needs to compute PRACH length), but
the driver itself does not depend on nor does it need the ASN.1 NR RRC
headers. Defining a new header avoids the problem.
Romain Beurdouche
42b5df351d