as3525v1: drop the asm version of mono2stereo

When building with eabi gcc, 2 variables are assigned the same register
This might be a bug in the constraints, but it's just simpler to use C,
even at the cost of 1 cycle per loop

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@26761 a1c6a512-1295-4272-9138-f99709370657

firmware/target/arm/as3525/pcm-as3525.c

@@ -263,7 +263,7 @@ static inline void mono2stereo(int16_t *end)
 {
     if(audio_channels != 1) /* only for microphone */
         return;
-#if 0
+
     /* load pointer in a register and avoid updating it in each loop */
     register int16_t *samples = mono_samples;
 
@@ -273,19 +273,6 @@ static inline void mono2stereo(int16_t *end)
     } while(samples != end);
 
     mono_samples = samples; /* update pointer */
-#else
-    /* gcc doesn't use pre indexing : let's save 1 cycle */
-    int16_t left;
-    asm (
-        "1: ldrh %0, [%1], #2   \n" // load 1 sample of the left-channel
-        "   strh %0, [%1], #2   \n" // copy it in the right-channel
-        "   cmp %1, %2          \n" // are we finished?
-        "   bne  1b             \n"
-        : "=r"(left), "+r"(mono_samples)
-        : "r"(end)
-        : "memory"
-    );
-#endif /* C / ASM */
 }
 #endif /* CONFIG_CPU == AS3525 */