rasops(9): Remove dead assignment

[Frederic Cambus]

Hi tech@,

Now that we call rasops_putchar_rotated(), we don't need ri anymore.

Comments? OK?

Index: sys/dev/rasops/rasops.c
===================================================================
RCS file: /cvs/src/sys/dev/rasops/rasops.c,v
retrieving revision 1.48
diff -u -p -r1.48 rasops.c
--- sys/dev/rasops/rasops.c     22 Aug 2017 12:24:45 -0000      1.48
+++ sys/dev/rasops/rasops.c     22 Dec 2017 21:08:39 -0000
@@ -1265,11 +1265,8 @@ rasops_putchar_rotated(void *cookie, int
 int
 rasops_erasecols_rotated(void *cookie, int row, int col, int num, long attr)
 {
-       struct rasops_info *ri;
        int i;
        int rc;
-
-       ri = (struct rasops_info *)cookie;
 
        for (i = col; i < col + num; i++) {
                rc = rasops_putchar_rotated(cookie, row, i, ' ', attr);