Add KVX MPPA detection

* config.guess (kvx:Linux:*:*, kvx:cos:*:*, kvx:mbr:*:*): Recognize.
* config.sub (kvx): Recognize cpu.
(cos*, mbr*): Recognize os.
* testsuite/config-guess.data: Add tests for kvx targets.
* testsuite/config-sub.data: Likewise.
* doc/config.guess.1: Regenerate.
* doc/config.sub.1: Likewise.

config.sub

@@ -4,7 +4,7 @@
 
 # shellcheck disable=SC2006,SC2268 # see below for rationale
 
-timestamp='2023-07-13'
+timestamp='2023-07-19'
 
 # This file is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by
@@ -1206,6 +1206,7 @@ case $cpu-$vendor in
 			| i370 | i*86 | i860 | i960 | ia16 | ia64 \
 			| ip2k | iq2000 \
 			| k1om \
+			| kvx \
 			| le32 | le64 \
 			| lm32 \
 			| loongarch32 | loongarch64 \
@@ -1759,7 +1760,7 @@ case $os in
 	     | onefs* | tirtos* | phoenix* | fuchsia* | redox* | bme* \
 	     | midnightbsd* | amdhsa* | unleashed* | emscripten* | wasi* \
 	     | nsk* | powerunix* | genode* | zvmoe* | qnx* | emx* | zephyr* \
-	     | fiwix* | mlibc* )
+	     | fiwix* | mlibc* | cos* | mbr* )
 		;;
 	# This one is extra strict with allowed versions
 	sco3.2v2 | sco3.2v[4-9]* | sco5v6*)