powerpc: remove GCC version check for UPD_CONSTR

Now that GCC 5.1 is the minimum supported version, we can drop this
workaround for older versions of GCC. This adversely affected clang,
too.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/include/asm/asm-const.h

@@ -12,16 +12,6 @@
 #  define ASM_CONST(x)		__ASM_CONST(x)
 #endif
 
-/*
- * Inline assembly memory constraint
- *
- * GCC 4.9 doesn't properly handle pre update memory constraint "m<>"
- *
- */
-#if defined(GCC_VERSION) && GCC_VERSION < 50000
-#define UPD_CONSTR ""
-#else
 #define UPD_CONSTR "<>"
-#endif
 
 #endif /* _ASM_POWERPC_ASM_CONST_H */