drivers/media/IR/ir-keytable.c: fix binary search

The input-large-scancode patches changed the binary search in
drivers/media/IR/ir-keytable.c to use unsigned integers, but
signed integers are actually necessary for the algorithm to work.

Signed-off-by: David Härdeman <[e-mail]>
Cc: Dmitry Torokhov <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/media/IR/ir-keytable.c

···
 static unsigned int ir_lookup_by_scancode(const struct ir_scancode_table *rc_tab,
 					  unsigned int scancode)
 {
-	unsigned int start = 0;
-	unsigned int end = rc_tab->len - 1;
-	unsigned int mid;
+	int start = 0;
+	int end = rc_tab->len - 1;
+	int mid;
 
 	while (start <= end) {
 		mid = (start + end) / 2;