UPSTREAM: linux/limits.h: Extract common header for vDSO

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.

Split limits.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-4-vincenzo.frascino@arm.com


(cherry picked from commit 3e0e9f8c6e3ca92154a74edc23a8872da921d2b6)
Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 154668398
Change-Id: I44a17919f0155af9efcb514041c01350bb80c16f