Rename a function to avoid a clash

We already have a constant_time_select() function so, to avoid
confusion/clashing we shouldn't have a second one.
Reviewed-by: NBernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/5105)

crypto/ec/curve448/constant_time.h

@@ -258,12 +258,12 @@ static ossl_inline void constant_time_lookup(void *RESTRICT out_,
  * Note that the output is not __restrict__, but if it overlaps either
  * input, it must be equal and not partially overlap.
  */
-static ossl_inline void constant_time_select(void *a_,
-                                             const void *bFalse_,
-                                             const void *bTrue_,
-                                             word_t elem_bytes,
-                                             mask_t mask,
-                                             size_t alignment_bytes)
+static ossl_inline void constant_time_select_c448(void *a_,
+                                                  const void *bFalse_,
+                                                  const void *bTrue_,
+                                                  word_t elem_bytes,
+                                                  mask_t mask,
+                                                  size_t alignment_bytes)
 {
     unsigned char *a = (unsigned char *)a_;
     const unsigned char *bTrue = (const unsigned char *)bTrue_;

crypto/ec/curve448/field.h

@@ -128,7 +128,7 @@ static ossl_inline void gf_mulw(gf c, const gf a, int32_t w)
 /* Constant time, x = is_z ? z : y */
 static ossl_inline void gf_cond_sel(gf x, const gf y, const gf z, mask_t is_z)
 {
-    constant_time_select(x, y, z, sizeof(gf), is_z, 0);
+    constant_time_select_c448(x, y, z, sizeof(gf), is_z, 0);
 }
 
 /* Constant time, if (neg) x=-x; */