kgdb: remove #include <linux/serial_8250.h> from kgdb.h

There's no reason kgdb.h itself needs to include the 8250 serial port
header file.  So push it down to the _very_ limited number of individual
drivers that need the values in that file, and fix up the places where
people really wanted serial_core.h and platform_device.h.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 9a61738..c26278f 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -29,6 +29,7 @@
  */
 #include <linux/pid_namespace.h>
 #include <linux/clocksource.h>
+#include <linux/serial_core.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
 #include <linux/console.h>
diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index ce615e0..38573f3 100644
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -31,6 +31,7 @@
 #include <linux/kernel.h>
 #include <linux/kgdb.h>
 #include <linux/kdb.h>
+#include <linux/serial_core.h>
 #include <linux/reboot.h>
 #include <linux/uaccess.h>
 #include <asm/cacheflush.h>