_update_kernel_cmdline handles two cmdline parameters at once. This does not
only make the function itself but also its callers more complicated than
necessary. For example in _update_crashkernel the fadump gets "updated" to
the value that has been read from grubby. Thus simplify
_update_kernel_cmdline to only update one parameter at once.
While at it shorten some variable named in the callers.
Signed-off-by: Philipp Rudo <prudo@redhat.com>
Reviewed-by: Pingfan Liu <piliu@redhat.com>
