docs: Get rid of the badRAM guide

The last release of this tool was for 2.6.28; it's hard to see how it has
any relevance to current kernels.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/bad-memory.rst

-How to deal with bad memory e.g. reported by memtest86+ ?
-=========================================================
-
-March 2008
-Jan-Simon Moeller, dl9pf@gmx.de
-
-
-
-There are three possibilities I know of:
-
-1) Reinsert/swap the memory modules
-
-2) Buy new modules (best!) or try to exchange the memory
-   if you have spare-parts
-
-3) Use BadRAM or memmap
-
-This Howto is about number 3) .
-
-
-BadRAM
-######
-
-BadRAM is the actively developed and available as kernel-patch
-here:  http://rick.vanrein.org/linux/badram/
-
-For more details see the BadRAM documentation.
-
-memmap
-######
-
-memmap is already in the kernel and usable as kernel-parameter at
-boot-time.  Its syntax is slightly strange and you may need to
-calculate the values by yourself!
-
-Syntax to exclude a memory area (see admin-guide/kernel-parameters.rst for details)::
-
-	memmap=<size>$<address>
-
-Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
-some others. All had 0x1869xxxx in common, so I chose a pattern of
-0x18690000,0xffff0000.
-
-With the numbers of the example above::
-
-	memmap=64K$0x18690000
-
-or::
-
-	memmap=0x10000$0x18690000

Documentation/admin-guide/index.rst

@@ -58,5 +58,4 @@ configure specific aspects of kernel behavior to your liking.
    binfmt-misc
    mono
    java
-   bad-memory
    basic-profiling