Express new ELF32 mechanisms in documentation

This patch reflects the
http://git.kernel.org/?p=linux/kernel/git/horms/kexec-tools-testing.git;a=commit;h=b9c3648e690ad0dad12389659673206213a09760
change in kexec-tools-testing also now in the kernel documentation.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Haren Myneni <hbabu@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kdump/kdump.txt

@@ -301,11 +301,13 @@ For ppc64:
 Notes on loading the dump-capture kernel:
 
 * By default, the ELF headers are stored in ELF64 format to support
-  systems with more than 4GB memory. The --elf32-core-headers option can
-  be used to force the generation of ELF32 headers. This is necessary
-  because GDB currently cannot open vmcore files with ELF64 headers on
-  32-bit systems. ELF32 headers can be used on non-PAE systems (that is,
-  less than 4GB of memory).
+  systems with more than 4GB memory. On i386, kexec automatically checks if
+  the physical RAM size exceeds the 4 GB limit and if not, uses ELF32.
+  So, on non-PAE systems, ELF32 is always used.
+
+  The --elf32-core-headers option can be used to force the generation of ELF32
+  headers. This is necessary because GDB currently cannot open vmcore files
+  with ELF64 headers on 32-bit systems.
 
 * The "irqpoll" boot parameter reduces driver initialization failures
   due to shared interrupts in the dump-capture kernel.