alpha: Eliminate compiler warning from memset macro

Compiling with GCC 4.8 yields several instances of

crypto/vmac.c: In function ‘vmac_final’:
crypto/vmac.c:616:9: warning: value computed is not used [-Wunused-value]
  memset(&mac, 0, sizeof(vmac_t));
         ^
arch/alpha/include/asm/string.h:31:25: note: in definition of macro ‘memset’
     ? __builtin_memset((s),0,(n))          \
                         ^
Converting the macro to an inline function eliminates this problem.

However, doing only that causes problems with the GCC 3.x series.  The
inline function cannot be named "memset", as otherwise we wind up with
recursion via __builtin_memset.  Solve this by adjusting the symbols
such that __memset is the inline, and ___memset is the real function.

Signed-off-by: Richard Henderson <rth@twiddle.net>

arch/alpha/lib/ev6-memset.S

@@ -30,14 +30,15 @@
 	.set noat
 	.set noreorder
 .text
+	.globl memset
 	.globl __memset
+	.globl ___memset
 	.globl __memsetw
 	.globl __constant_c_memset
-	.globl memset
 
-	.ent __memset
+	.ent ___memset
 .align 5
-__memset:
+___memset:
 	.frame $30,0,$26,0
 	.prologue 0
 
@@ -227,7 +228,7 @@ end_b:
 	nop
 	nop
 	ret $31,($26),1		# L0 :
-	.end __memset
+	.end ___memset
 
 	/*
 	 * This is the original body of code, prior to replication and
@@ -594,4 +595,5 @@ end_w:
 
 	.end __memsetw
 
-memset = __memset
+memset = ___memset
+__memset = ___memset