mips/kexec: refactor for kernel/Kconfig.kexec

The kexec and crash kernel options are provided in the common
kernel/Kconfig.kexec. Utilize the common options and provide
the ARCH_SUPPORTS_ and ARCH_SELECTS_ entries to recreate the
equivalent set of KEXEC and CRASH options.

Link: https://lkml.kernel.org/r/20230712161545.87870-9-eric.devolder@oracle.com
Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

arch/mips/Kconfig

@@ -2878,33 +2878,11 @@ config HZ
 config SCHED_HRTICK
 	def_bool HIGH_RES_TIMERS
 
-config KEXEC
-	bool "Kexec system call"
-	select KEXEC_CORE
-	help
-	  kexec is a system call that implements the ability to shutdown your
-	  current kernel, and to start another kernel.  It is like a reboot
-	  but it is independent of the system firmware.   And like a reboot
-	  you can start any kernel with it, not just Linux.
+config ARCH_SUPPORTS_KEXEC
+	def_bool y
 
-	  The name comes from the similarity to the exec system call.
-
-	  It is an ongoing process to be certain the hardware in a machine
-	  is properly shutdown, so do not be surprised if this code does not
-	  initially work for you.  As of this writing the exact hardware
-	  interface is strongly in flux, so no good recommendation can be
-	  made.
-
-config CRASH_DUMP
-	bool "Kernel crash dumps"
-	help
-	  Generate crash dump after being started by kexec.
-	  This should be normally only set in special crash dump kernels
-	  which are loaded in the main kernel with kexec-tools into
-	  a specially reserved region and then later executed after
-	  a crash by kdump/kexec. The crash dump kernel must be compiled
-	  to a memory address not used by the main kernel or firmware using
-	  PHYSICAL_START.
+config ARCH_SUPPORTS_CRASH_DUMP
+	def_bool y
 
 config PHYSICAL_START
 	hex "Physical address where the kernel is loaded"