kbuild: try harder to find symbol names in modpost

The relocation record sometimes contained an address
which was not an exactly match for a symbol.

Implment some simple logic such that if there
is a symbol within 20 bytes of the address contained
in the relocation record then print the name of this
symbol.

With this change modpost could find symbol names
for the remaining .init.text symbols in my
allyesconfig build for x86_64.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
index 0ffed17..999f15e 100644
--- a/scripts/mod/modpost.h
+++ b/scripts/mod/modpost.h
@@ -17,6 +17,7 @@
 #define Elf_Shdr    Elf32_Shdr
 #define Elf_Sym     Elf32_Sym
 #define Elf_Addr    Elf32_Addr
+#define Elf_Sword   Elf64_Sword
 #define Elf_Section Elf32_Half
 #define ELF_ST_BIND ELF32_ST_BIND
 #define ELF_ST_TYPE ELF32_ST_TYPE
@@ -31,6 +32,7 @@
 #define Elf_Shdr    Elf64_Shdr
 #define Elf_Sym     Elf64_Sym
 #define Elf_Addr    Elf64_Addr
+#define Elf_Sword   Elf64_Sxword
 #define Elf_Section Elf64_Half
 #define ELF_ST_BIND ELF64_ST_BIND
 #define ELF_ST_TYPE ELF64_ST_TYPE