Rename poly1305_setkey() to poly1305_starts()

For consistency with the existing CMAC and HMAC APIs

include/mbedtls/poly1305.h

diff --git a/include/mbedtls/poly1305.h b/include/mbedtls/poly1305.h
index c911b9f..f691915 100644
--- a/include/mbedtls/poly1305.h
+++ b/include/mbedtls/poly1305.h
@@ -81,7 +81,7 @@
  *                      or key are NULL.
  *                      Otherwise, 0 is returned to indicate success.
  */
-int mbedtls_poly1305_setkey( mbedtls_poly1305_context *ctx,
+int mbedtls_poly1305_starts( mbedtls_poly1305_context *ctx,
                              const unsigned char key[32] );
 
 /**

library/aead_chacha20_poly1305.c

diff --git a/library/aead_chacha20_poly1305.c b/library/aead_chacha20_poly1305.c
index f00380c..0418008 100644
--- a/library/aead_chacha20_poly1305.c
+++ b/library/aead_chacha20_poly1305.c
@@ -155,7 +155,7 @@
     if ( result != 0 )
         goto cleanup;
 
-    result = mbedtls_poly1305_setkey( &ctx->poly1305_ctx, poly1305_key );
+    result = mbedtls_poly1305_starts( &ctx->poly1305_ctx, poly1305_key );
 
     if ( result == 0 )
     {

library/poly1305.c

diff --git a/library/poly1305.c b/library/poly1305.c
index 5a09658..66f932c 100644
--- a/library/poly1305.c
+++ b/library/poly1305.c
@@ -256,7 +256,7 @@
     }
 }
 
-int mbedtls_poly1305_setkey( mbedtls_poly1305_context *ctx,
+int mbedtls_poly1305_starts( mbedtls_poly1305_context *ctx,
                              const unsigned char key[32] )
 {
     if ( ctx == NULL )
@@ -400,7 +400,7 @@
 
     mbedtls_poly1305_init( &ctx );
 
-    result = mbedtls_poly1305_setkey( &ctx, key );
+    result = mbedtls_poly1305_starts( &ctx, key );
     if ( result != 0 )
         goto cleanup;