patch 8.2.1898: command modifier parsing always uses global cmdmod

Problem:    Command modifier parsing always uses global cmdmod.
Solution:   Pass in cmdmod_T to use.  Rename struct fields consistently.
diff --git a/src/register.c b/src/register.c
index ca74aee..4c7c511 100644
--- a/src/register.c
+++ b/src/register.c
@@ -1358,7 +1358,7 @@
 	}
     }
 
-    if (!cmdmod.lockmarks)
+    if ((cmdmod.cmod_flags & CMOD_LOCKMARKS) == 0)
     {
 	// Set "'[" and "']" marks.
 	curbuf->b_op_start = oap->start;
@@ -2170,7 +2170,7 @@
     curwin->w_set_curswant = TRUE;
 
 end:
-    if (cmdmod.lockmarks)
+    if (cmdmod.cmod_flags & CMOD_LOCKMARKS)
     {
 	curbuf->b_op_start = orig_start;
 	curbuf->b_op_end = orig_end;