Fix nistp512 typos, should be nistp521

Note, this now compiles, but fails tests, so further remediation
is required.

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>

crypto/ec/ec_lcl.h

diff --git a/crypto/ec/ec_lcl.h b/crypto/ec/ec_lcl.h
index 036f9ee..36432e1 100644
--- a/crypto/ec/ec_lcl.h
+++ b/crypto/ec/ec_lcl.h
@@ -203,7 +203,7 @@
  */
 typedef struct nistp224_pre_comp_st NISTP224_PRE_COMP;
 typedef struct nistp256_pre_comp_st NISTP256_PRE_COMP;
-typedef struct nistp512_pre_comp_st NISTP521_PRE_COMP;
+typedef struct nistp521_pre_comp_st NISTP521_PRE_COMP;
 typedef struct nistz256_pre_comp_st NISTZ256_PRE_COMP;
 typedef struct ec_pre_comp_st EC_PRE_COMP;
 

crypto/ec/ecp_nistp521.c

diff --git a/crypto/ec/ecp_nistp521.c b/crypto/ec/ecp_nistp521.c
index 97744b2..516101c 100644
--- a/crypto/ec/ecp_nistp521.c
+++ b/crypto/ec/ecp_nistp521.c
@@ -1585,7 +1585,7 @@
 }
 
 /* Precomputation for the group generator. */
-struct nistp512_pre_comp_st {
+struct nistp521_pre_comp_st {
     felem g_pre_comp[16][3];
     int references;
 };
@@ -2104,7 +2104,7 @@
 
 int ec_GFp_nistp521_have_precompute_mult(const EC_GROUP *group)
 {
-    return HAVEPRECOMP(group, nistp512);
+    return HAVEPRECOMP(group, nistp521);
 }
 
 #else