ARM: add kexec_file_load system call number

A couple of architectures including arm64 already implement the
kexec_file_load system call, on many others we have assigned a system
call number for it, but not implemented it yet.

Adding the number in arch/arm/ lets us use the system call on arm64
systems in compat mode, and also reduces the number of differences
between architectures. If we want to implement kexec_file_load on ARM
in the future, the number assignment means that kexec tools can already
be built with the now current set of kernel headers.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/tools/syscall.tbl

@@ -415,3 +415,4 @@
 398	common	rseq			sys_rseq
 399	common	io_pgetevents		sys_io_pgetevents
 400	common	migrate_pages		sys_migrate_pages
+401	common	kexec_file_load		sys_kexec_file_load

arch/arm64/include/asm/unistd.h

@@ -44,7 +44,7 @@
 #define __ARM_NR_compat_set_tls		(__ARM_NR_COMPAT_BASE + 5)
 #define __ARM_NR_COMPAT_END		(__ARM_NR_COMPAT_BASE + 0x800)
 
-#define __NR_compat_syscalls		401
+#define __NR_compat_syscalls		402
 #endif
 
 #define __ARCH_WANT_SYS_CLONE

arch/arm64/include/asm/unistd32.h

@@ -823,6 +823,8 @@ __SYSCALL(__NR_rseq, sys_rseq)
 __SYSCALL(__NR_io_pgetevents, compat_sys_io_pgetevents)
 #define __NR_migrate_pages 400
 __SYSCALL(__NR_migrate_pages, compat_sys_migrate_pages)
+#define __NR_kexec_file_load 401
+__SYSCALL(__NR_kexec_file_load, sys_kexec_file_load)
 
 /*
  * Please add new compat syscalls above this comment and update