modprobe: Make rmmod_do_module() contain all the removal sequence

modprobe: Make rmmod_do_module() contain all the removal sequence

Move the remaining part of the removal sequence dangling in
rmmod_do_remove_module() to rmmod_do_module() so we can consider this
function is the one controlling all the module removals.

While at it, add some comments about the removal order and normalize
coding style in this function.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>