linker: simpler encoding for SHT_RELR sections.

This change modifies the encoding used in SHT_RELR sections to a simpler
version that gives better results. This encoding was suggested by Andrew
Grieve and is described in this post on generic-abi@googlegroups.com:
    https://groups.google.com/d/msg/generic-abi/bX460iggiKg/Pi9aSwwABgAJ

Bug: None
Test: Built image for marlin, flashed on device, ran arm and
      aarch64 binaries containing '.relr.dyn' sections using
      the new encoding.

Change-Id: I266affe0fbad91dc375995985a221cb02499447b
diff --git a/libc/include/elf.h b/libc/include/elf.h
index bda11f5..a8d62db 100644
--- a/libc/include/elf.h
+++ b/libc/include/elf.h
@@ -194,13 +194,9 @@
   Elf64_Word vna_next;
 } Elf64_Vernaux;
 
-/* Relocation table entry for relative (in section of type SHT_RELR).  */
+/* Relocation table entry for relative (in section of type SHT_RELR). */
 typedef Elf32_Word Elf32_Relr;
 typedef Elf64_Xword Elf64_Relr;
-#define ELF32_R_JUMP(val) ((val) >> 24)
-#define ELF32_R_BITS(val) ((val) & 0xffffff)
-#define ELF64_R_JUMP(val) ((val) >> 56)
-#define ELF64_R_BITS(val) ((val) & 0xffffffffffffff)
 
 /* http://www.sco.com/developers/gabi/latest/ch5.dynamic.html */
 #define DF_ORIGIN     0x00000001