VFS: Minor fixes for porting.rst

This paragraph was relevant for an earlier version of the code which
passed the qstr as a struct instead of a point.  The version that landed
passed the pointer in all cases so this para is now pointless.

Signed-off-by: NeilBrown <neil@brown.name>
Link: https://lore.kernel.org/20250608230952.20539-3-neil@brown.name


Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>