imgact_elf: accept .note.ABI-tag sections located anywhere

imgact_elf: accept .note.ABI-tag sections located anywhere

This follows up on commit d9f47b9b82dc9e762119fd00267eef9a0268680a.

While our current build infrastructure now produces binaries which can
be read properly by the kernel, this does not hold true for any non-base
linker, particularly binutils compiled directly from source, or even the
recent binutils-2.20 import.

Instead of relying on local modifications to the Elf linker scripts,
bite the bullet and make the kernel deal with PT_NOTE sections that lie
outside the first page.