drivers/char: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required

They will need it called out explicitly in the near future due
to a module.h usage cleanup that removes its implicit presence
everywhere.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

drivers/char/mem.c

@@ -26,6 +26,7 @@
 #include <linux/bootmem.h>
 #include <linux/splice.h>
 #include <linux/pfn.h>
+#include <linux/export.h>
 
 #include <asm/uaccess.h>
 #include <asm/io.h>

drivers/char/ttyprintk.c

@@ -17,6 +17,7 @@
 #include <linux/device.h>
 #include <linux/serial.h>
 #include <linux/tty.h>
+#include <linux/export.h>
 
 struct ttyprintk_port {
 	struct tty_port port;