elf, uapi: Add type ElfXX_Versym

The type is used by tools/testing/selftests/vDSO/parse_vdso.c.

To be able to build the vDSO selftests without a libc dependency,
add the type to the kernels own UAPI headers. As documented by elf(5).

Signed-off-by: Thomas Weißschuh <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Reviewed-by: Kees Cook <[e-mail]>
Reviewed-by: Vincenzo Frascino <[e-mail]>
Acked-by: Shuah Khan <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]

include/uapi/linux/elf.h

···
 typedef __u32	Elf32_Off;
 typedef __s32	Elf32_Sword;
 typedef __u32	Elf32_Word;
+typedef __u16	Elf32_Versym;
 
 /* 64-bit ELF base types. */
 typedef __u64	Elf64_Addr;
···
 typedef __u32	Elf64_Word;
 typedef __u64	Elf64_Xword;
 typedef __s64	Elf64_Sxword;
+typedef __u16	Elf64_Versym;
 
 /* These constants are for the segment types stored in the image headers */
 #define PT_NULL    0