kbuild: change module.order to list *.o instead of *.ko

kbuild: change module.order to list *.o instead of *.ko

scripts/Makefile.build replaces the suffix .o with .ko, then
scripts/Makefile.modpost calls the sed command to change .ko back
to the original .o suffix.

Instead of converting the suffixes back-and-forth, store the .o paths
in modules.order, and replace it with .ko in 'make modules_install'.

This avoids the unneeded sed command.

Signed-off-by: Masahiro Yamada <[email protected]>
Reviewed-by: Luis Chamberlain <[email protected]>