arm: Fix addressing in optpld macro

In patch b219285f87 you have a syntax
error in the PLD instruction.  The syntax for the pld argument should be
in square brackets as it's a memory address like so: pld [r1].  With
your patch the newlib build fails for armv7-a targets.  This patch fixes
the build failures.

Tested by making sure the newlib build completes successfully.

2016-01-26  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>

    * libc/machine/arm/strcpy.c (strcpy): Fix PLD assembly syntax.
    * libc/machine/arm/strlen-stub.c (strlen): Likewise.

newlib/libc/machine/arm/strcpy.c

@@ -45,7 +45,7 @@ strcpy (char* dst, const char* src)
 #if !(defined(__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED) || \
       (defined (__thumb__) && !defined (__thumb2__)))
 #ifdef _ISA_ARM_7
-       "pld	r1\n\t"
+       "pld	[r1]\n\t"
 #endif
        "eor	r2, r0, r1\n\t"
        "mov	ip, r0\n\t"
@@ -78,7 +78,7 @@ strcpy (char* dst, const char* src)
        ".p2align 2\n"
   "2:\n\t"
 #ifdef _ISA_ARM_7
-       "pld	r1, #8\n\t"
+       "pld	[r1, #8]\n\t"
 #endif
        "ldr	r4, [r1], #4\n\t"
        "sub	r2, r3, "magic1(r5)"\n\t"

newlib/libc/machine/arm/strlen-stub.c

@@ -59,7 +59,7 @@ strlen (const char* str)
        "addr .req r1\n\t"
 
 #ifdef _ISA_ARM_7
-       "pld r0\n\t"
+       "pld [r0]\n\t"
 #endif
        /* Word-align address */
        "bic	addr, r0, #3\n\t"
@@ -116,7 +116,7 @@ strlen (const char* str)
        /* and 4 more bytes  */
        "addeq	len, len, #4\n\t"
 	/* Unroll the loop a bit.  */
-       "pld	addr, #8\n\t"
+       "pld	[addr, #8]\n\t"
        /*  test (data - 0x01010101)  */
        "ittt	eq\n\t"
        "subeq	r2, data, ip\n\t"