kmodloader: use the name of the found module struct for modinfo

kmodloader: use the name of the found module struct for modinfo

The module .ko file might be called differently than the name used
by the kernel internally, e.g. "nls_iso8859-1.ko" is called
"nls_iso8859_1" in lsmmod. The print_modinfo() procedure expects the
filename spelling in order to successfully resolve the full module path.

After this change, "modinfo" supports printing module info even if the
user gives the kernel internal spelling instead of the file name one,
so that e.g. "modinfo "nls_iso8859_1" and "modinfo nls_iso8859-1.ko" will
both succeed.