UPSTREAM: linux/elfnote.h: Replace elf.h with UAPI equivalent

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Replace linux/elf.h with UAPI equivalent in elfnote.h to make the header
suitable for vDSO inclusion.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-18-vincenzo.frascino@arm.com


(cherry picked from commit b558051725c5f7caa1f390ab28f3ab9db085cbfc)
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 154668398
Change-Id: Ia80df895c00cf38e1d62231ca3f7700f557e1342