common: remove bedbug debugger support

Commit 98f705c9ce ("powerpc: remove 4xx support") removed (in 2017) the
last code that made use of bedbug debugger support. Since there aren't
any boards left that define either CONFIG_CMD_BEDBUG or a real
bedbug_init(), drop this feature from u-boot.

Signed-off-by: Ovidiu Panait <ovidiu.panait@windriver.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

post/lib_powerpc/string.c

@@ -26,7 +26,6 @@ extern void cpu_post_exec_02 (ulong *code, ulong op1, ulong op2);
 extern void cpu_post_exec_04 (ulong *code, ulong op1, ulong op2, ulong op3,
     ulong op4);
 
-#include <bedbug/regs.h>
 int cpu_post_test_string (void)
 {
     int ret = 0;