kexec: generate VMCOREINFO for module symbols

kexec: generate VMCOREINFO for module symbols

This commit is one of the three commit for generating VMCOREINFO
symbol information.  See comments in previous two commits.

To dump kallsyms, module symbols must also be included.  The
symbol table of each module can be located through the module
list.  This commit generates necessary symbol information for
accessing the symbol tables of loaded modules.

Orabug: 29770217
Signed-off-by: Isaac Chen <isaac.chen@oracle.com>
Reviewed-by: Joe Jin <joe.jin@oracle.com>
Signed-off-by: Brian Maly <brian.maly@oracle.com>