[PATCH] shared library support for MMUless binfmt_flat loader

This patch adds shared library support to the MMU application
loader, binfmt_flat. This is not new, it is a forward port from the
same support in 2.4.x kernels with MMUless support, and has been
running for well over a year now. The code support is conditionally
compiled on CONFIG_BINFMT_FLAT_SHARED. This change also abstracts
a bit more architecture dependent code into the separate flat.h
includes.

Basically relocations within an application also carry a tag to
identify what they refer too (this code or which shared library).
This is patched as before at load/run-time with an appropriate
address.