Relocations: Fix some 32 bit relocations

Fix for issue #564

The following 32 bit relocations were set as signed but should be bitfield:
 ARC_32_ME, ARC_GLOB_DAT, ARC_JMP_SLOT, ARC_RELATIVE

Signed-off-by: Bruno Mauricio <brunoasmauricio@gmail.com>

Author: BrunoASMauricio

include/elf/arc-reloc.def

@@ -208,7 +208,7 @@ ARC_RELOC_HOWTO(ARC_32_ME, 27, \
                 4, \
                 32, \
                 replace_limm, \
-                signed, \
+                bitfield, \
                 ( ME ( ( S + A ) ) ))
 
 ARC_RELOC_HOWTO(ARC_32_ME_S, 105, \
@@ -376,21 +376,21 @@ ARC_RELOC_HOWTO(ARC_GLOB_DAT, 54, \
                 4, \
                 32, \
                 replace_word32, \
-                signed, \
+                bitfield, \
                 S)
 
 ARC_RELOC_HOWTO(ARC_JMP_SLOT, 55, \
                 4, \
                 32, \
                 replace_word32, \
-                signed, \
+                bitfield, \
                 ( ME ( S ) ))
 
 ARC_RELOC_HOWTO(ARC_RELATIVE, 56, \
                 4, \
                 32, \
                 replace_word32, \
-                signed, \
+                bitfield, \
                 ( ME ( ( B + A ) ) ))
 
 ARC_RELOC_HOWTO(ARC_GOTOFF, 57, \