s390/Kconfig: Move kexec config options to "Processor type and features"

The config options for kexec are currently not under any menu directory. Up
until now this was not a problem as standard kexec is always compiled in
and thus does not create a menu entry. This changed when kexec_file_load
was enabled. Its config option requires a menu entry which, when added
beneath standard kexec option, appears on the main directory above "General
Setup". Thus move the whole block further down such that the entry in now
in "Processor type and features".

While at it also update the help text for kexec file.
Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -47,27 +47,6 @@ config PGSTE
 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
 	def_bool y
 
-config KEXEC
-	def_bool y
-	select KEXEC_CORE
-
-config KEXEC_FILE
-	bool "kexec file based system call"
-	select KEXEC_CORE
-	select BUILD_BIN2C
-	depends on CRYPTO
-	depends on CRYPTO_SHA256
-	depends on CRYPTO_SHA256_S390
-	---help---
-	  This is new version of kexec system call. This system call is
-	  file based and takes file descriptors as system call argument
-	  for kernel and initramfs as opposed to list of segments as
-	  accepted by previous system call.
-
-config ARCH_HAS_KEXEC_PURGATORY
-	def_bool y
-	depends on KEXEC_FILE
-
 config AUDIT_ARCH
 	def_bool y
 
@@ -542,6 +521,26 @@ source kernel/Kconfig.preempt
 
 source kernel/Kconfig.hz
 
+config KEXEC
+	def_bool y
+	select KEXEC_CORE
+
+config KEXEC_FILE
+	bool "kexec file based system call"
+	select KEXEC_CORE
+	select BUILD_BIN2C
+	depends on CRYPTO
+	depends on CRYPTO_SHA256
+	depends on CRYPTO_SHA256_S390
+	help
+	  Enable the kexec file based system call. In contrast to the normal
+	  kexec system call this system call takes file descriptors for the
+	  kernel and initramfs as arguments.
+
+config ARCH_HAS_KEXEC_PURGATORY
+	def_bool y
+	depends on KEXEC_FILE
+
 config ARCH_RANDOM
 	def_bool y
 	prompt "s390 architectural random number generation API"