merge add-patches-section functionality into create-obj-diff

In preparation for dynamic symbol linking, the symbol lookup logic
is going to move into create-diff-obj anyway.  We might as well
minimize the code duplication and pull this into create-diff-obj.
This avoids having to re-parse the ELF file modify it in-place.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
rename .patches section to .kpatch.patches

Adding .kpatch to the section name more clearly documents that these
are kpatch related sections.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
dynrelas support, obsoleting link-vmlinux-syms

This adds dynamic linking support for the patch modules.  It is the
first step toward supporting patching module code and relocatable
kernels.

Rela entries that reference non-included local and non-exported global
symbols are converted to "dynrelas".  These dynrelas are relocations
that are done by the core module, not the kernel module linker.  This
allows the core module to apply offsets to the base addresses found
in the base vmlinux or module.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
fix review comments

Signed-off-by: Seth Jennings <sjenning@redhat.com>