gcc-4.8: temporary disable thumb

gcc-4.8: temporary disable thumb

* temporary work around for build issue on armv4t:
  | cp/decl.o: In function `bad_specifiers':
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7171:(.text.unlikely+0x24): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7173:(.text.unlikely+0x32): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7176:(.text.unlikely+0x3e): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7180:(.text.unlikely+0x4c): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7182:(.text.unlikely+0x5a): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7185:(.text.unlikely+0x66): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7189:(.text.unlikely+0x74): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7191:(.text.unlikely+0x82): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7194:(.text.unlikely+0x8e): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7198:(.text.unlikely+0x9c): relocation truncated to fit: R_ARM_THM_CALL against symbol `error(char const*, ...)' defined in .glue_7 section in linker stubs
  | gcc-4.8.0-r0/gcc-4.8.0/gcc/cp/decl.c:7200:(.text.unlikely+0xaa): additional relocation overflows omitted from the output
  | collect2: error: ld returned 1 exit status
  | make[2]: *** [cc1plus] Error 1

(From OE-Core rev: 148c7e990831ed708f7fb064ec8f05657a323850)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>