crash: remove header files which are included more than once

Following warning is reported, so remove these duplicated header
including:

./kernel/crash_reserve.c: linux/kexec.h is included more than once.

This is just a clean code, no logic changed.

Link: https://lkml.kernel.org/r/20240606091427.3512314-1-haowenchao22@gmail.comSigned-off-by: Wenchao Hao <haowenchao22@gmail.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/crash_reserve.c

@@ -13,7 +13,6 @@
 #include <linux/memory.h>
 #include <linux/cpuhotplug.h>
 #include <linux/memblock.h>
-#include <linux/kexec.h>
 #include <linux/kmemleak.h>
 
 #include <asm/page.h>