Add big #ifdef CONFIG_MODULE around module.h to build architectures ...

which do not have modules.

__u_boot__symtab -> __usymtab

CONFIG_MODULE -> CONFIG_MODULES

Resolve the symbols using an extra section and only resolve explicitly ...

exported symbols. Using kallsyms for this purpose doesn't do it because
kallsyms do not resolve variables. Also the symbol table gets quite
big using kallsyms.

Add module handling (mostly copied from Linux kernel and stripped down ...

for U-Boot)