patch 8.1.1393: unnecessary type casts

Problem:    Unnecessary type casts.
Solution:   Remove type casts from alloc() and lalloc() calls. (Mike Williams)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 9f127ec..2b16a1e 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -4816,7 +4816,7 @@
 	    while ((pos = (char_u *)strstr((char *)pos + 2, "$*")) != NULL)
 		++i;
 	    len = (int)STRLEN(p);
-	    new_cmdline = alloc((int)(STRLEN(program) + i * (len - 2) + 1));
+	    new_cmdline = alloc(STRLEN(program) + i * (len - 2) + 1);
 	    if (new_cmdline == NULL)
 		return NULL;			/* out of memory */
 	    ptr = new_cmdline;
@@ -4832,7 +4832,7 @@
 	}
 	else
 	{
-	    new_cmdline = alloc((int)(STRLEN(program) + STRLEN(p) + 2));
+	    new_cmdline = alloc(STRLEN(program) + STRLEN(p) + 2);
 	    if (new_cmdline == NULL)
 		return NULL;			/* out of memory */
 	    STRCPY(new_cmdline, program);