[PATCH] x86_64: Don't do broadcast IPIs when hotplug is enabled in flat mode.
The use of non-shortcut version of routines breaking CPU hotplug. The option
to select this via cmdline also is deleted with the physflat patch, hence
directly placing this code under CONFIG_HOTPLUG_CPU.
We dont want to use broadcast mode IPI's when hotplug is enabled. This causes
bad effects in send IPI to a cpu that is offline which can trip when the cpu
is in the process of being kicked alive.