Found and fixed the issue for the kinetis-based boards: The kinetis
code is using some macros to map some IRQ names, that differ in
some versions of vendor headers, to a RIOT wide unique name. The
doxygen of this mapping states, that this mapping must be done before
any vendor header is included. Unfortunately, the mapping was so far
placed in cpu/kinetis/vectors.c, before any other include statement.
In some cases, the vendor headers might be included before the
mapping macros in vectors.c, leading to the compilation errors down
the line. To fix this, the adaption defines are moved into
cpu/kinetis/cpu_conf.h, which is the file that actually includes
the vendor headers. This way it is ensured, that these adaption
macros are always defined before any vendor header is included,
and therefore preventing this kind of error for good.
CPU_HAS_SRAM_BITBAND can be used to check whether bit-banding is supported for
all of SRAM. With partially supported bit-banding, this feature is more of a
foot gun that a valuable tool.
