elflink: Delete dump_elf_module()

elflink: Delete dump_elf_module()

dump_elf_module() doesn't have any callers (it's call site is
commented out in module_load()) and it's definition currently emits
the following build warning,

In file included from exit.c:34:0:
../include/sys/module.h: In function ‘dump_elf_module’:
../include/sys/module.h:123:55: warning: unused parameter ‘module’

Just delete it. If anyone needs a similar function in future it is
trivial to write.

Signed-off-by: Matt Fleming <matt.fleming@intel.com>