kbuild: whitelist false section mismatch warnings

In several cases the section mismatch check triggered false warnings.
Following patch introduce a whitelist to 'false positives' are not warned of.
Two types of patterns are recognised:
1) Typical case when a module parameter is _initdata
2) When a function pointer is assigned to a driver structure

In both patterns we rely on the actual name of the variable assigned

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>