dcda9f3 kernel-install: ignore extra args passed when invoked as installkernel

Authored and Committed by zbyszek 2 years ago
    kernel-install: ignore extra args passed when invoked as installkernel
    
    kernel's 'make install' invokes install.sh which calls /sbin/install-kernel.
    Thus we are invoked as e.g.
      /sbin/installkernel 5.18.0 arch/x86/boot/bzImage System.map /boot
    The last two arguments would be passed as "initrds".
    
    Before , we would just quitely ignore
    /boot, because it doesn't pass the 'test -f' test, and possibly try to do
    something with System.map. 742561efbe938c45936f2e4f5d81b3ff6b352882 tightened
    the check, so we now throw an error.
    
    It seems that the correct thing is to ignore those two arguments, because
    our plugin syntax has no notion of System.map. And the installation directory
    we can figure out ourselves better. Effectively, this makes things behave
    like before, but less by accident.
    
    Fixes #23490.
    
    (cherry picked from commit 620ecc9c4bb8769b2acb6c1b9b64b330d0f76fc1)