target: remove unused interface fn that clutters code

The quit entry point was not being invoked. Just a source
of confusion at this point. XScale ran 100x reset upon
quit, but that code made no sense, wasn't commented
and never invoke.

Signed-off-by: Øyvind Harboe <oyvind.harboe@zylin.com>

src/target/cortex_a8.c

@@ -106,7 +106,6 @@ target_type_t cortexa8_target =
 	.target_create = cortex_a8_target_create,
 	.init_target = cortex_a8_init_target,
 	.examine = cortex_a8_examine,
-	.quit = NULL
 };
 
 /*