Harcode curve in semi-internal modMult function

Saves 80 bytes of code size.
diff --git a/include/tinycrypt/ecc.h b/include/tinycrypt/ecc.h
index 7a0b0bb..ac3e3ad 100644
--- a/include/tinycrypt/ecc.h
+++ b/include/tinycrypt/ecc.h
@@ -367,8 +367,7 @@
  * @param Z IN -- z value
  * @param curve IN -- elliptic curve
  */
-void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z,
-	     uECC_Curve curve);
+void apply_z(uECC_word_t * X1, uECC_word_t * Y1, const uECC_word_t * const Z);
 
 /*
  * @brief Check if bit is set.
@@ -399,7 +398,7 @@
  * @param curve IN -- elliptic curve
  */
 void uECC_vli_modMult_fast(uECC_word_t *result, const uECC_word_t *left,
-			   const uECC_word_t *right, uECC_Curve curve);
+			   const uECC_word_t *right);
 
 /*
  * @brief Computes result = left - right.