Add separate labels for the start of public functions

This avoids having to use the public symbol name when jumping here,
on platforms where the public symbols have an underscore prefix.

Signed-off-by: Timothy B. Terriberry <tterribe@xiph.org>

celt/arm/celt_pitch_xcorr_arm.s

@@ -42,6 +42,7 @@ IF OPUS_ARM_MAY_HAVE_NEON
 
 ; Compute sum[k]=sum(x[j]*y[j+k],j=0...len-1), k=0...3
 xcorr_kernel_neon PROC
+xcorr_kernel_neon_start
   ; input:
   ;   r3     = int         len
   ;   r4     = opus_val16 *x
@@ -181,7 +182,7 @@ celt_pitch_xcorr_neon_process4
   VEOR         q0, q0, q0
   ; xcorr_kernel_neon only modifies r4, r5, r12, and q0...q3.
   ; So we don't save/restore any other registers.
-  BL xcorr_kernel_neon
+  BL xcorr_kernel_neon_start
   SUBS         r6, r6, #4
   VST1.32      {q0}, [r2]!
   ; _y += 4
@@ -257,6 +258,7 @@ IF OPUS_ARM_MAY_HAVE_EDSP
 ; This will get used on ARMv7 devices without NEON, so it has been optimized
 ; to take advantage of dual-issuing where possible.
 xcorr_kernel_edsp PROC
+xcorr_kernel_edsp_start
   ; input:
   ;   r3      = int         len
   ;   r4      = opus_val16 *_x (must be 32-bit aligned)
@@ -416,7 +418,7 @@ celt_pitch_xcorr_edsp_process4
   MOV          r7, #0
   MOV          r8, #0
   MOV          r9, #0
-  BL xcorr_kernel_edsp  ; xcorr_kernel_edsp(_x, _y+i, xcorr+i, len)
+  BL xcorr_kernel_edsp_start  ; xcorr_kernel_edsp(_x, _y+i, xcorr+i, len)
   ; maxcorr = max(maxcorr, sum0, sum1, sum2, sum3)
   CMP          r0, r6
   ; _y+=4