linux-imx

modpost: use linker section to generate table.

This means (most) future busses need only have one hunk in their
patch.  Also took the opportunity to check that function matches the
type.

Again, inspired by Alessandro's patch series.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alessandro Rubini <rubini@gnudd.com>