In order to keep the initialization process light-weight, remove
net_buf_pool_init() and instead perform the initialization of the pool
and buffers in a "lazy" manner. This means storing more information
in the pool, and removing any 'const' members from net_buf. Since
there are no more const members in net_buf the buffer array can be
declared with __noinit, which further reduces initialization overhead.
Change-Id: Ia126af101c2727c130651b697dcba99d159a1c76
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
71c7c01819