elf-em.h: add EM_CSKY

The uapi/linux/audit.h header is going to use EM_CSKY in order
to define AUDIT_ARCH_CSKY which is needed to implement
syscall_get_arch() which in turn is required to extend
the generic ptrace API with PTRACE_GET_SYSCALL_INFO request.

The value for EM_CSKY has been taken from arch/csky/include/asm/elf.h
and confirmed by binutils:include/elf/common.h

Cc: Guo Ren <guoren@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Elvira Khabirova <lineprinter@altlinux.org>
Cc: Eugene Syromyatnikov <esyr@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Signed-off-by: Guo Ren <guoren@kernel.org>

arch/csky/include/asm/elf.h

@@ -7,7 +7,7 @@
 #include <asm/ptrace.h>
 #include <abi/regdef.h>
 
-#define ELF_ARCH 252
+#define ELF_ARCH EM_CSKY
 
 /* CSKY Relocations */
 #define R_CSKY_NONE               0

include/uapi/linux/elf-em.h

@@ -43,6 +43,7 @@
 #define EM_TILEGX	191	/* Tilera TILE-Gx */
 #define EM_RISCV	243	/* RISC-V */
 #define EM_BPF		247	/* Linux BPF - in-kernel virtual machine */
+#define EM_CSKY		252	/* C-SKY */
 #define EM_FRV		0x5441	/* Fujitsu FR-V */
 
 /*