Kconfig: Remove hotplug enable hints in CONFIG_KEXEC help texts

commit 40b31360 ("Finally eradicate
CONFIG_HOTPLUG") removed remaining references to CONFIG_HOTPLUG, but missed
a few plain English references in the CONFIG_KEXEC help texts.

Remove them, too.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>