powerpc: add export.h to files making use of EXPORT_SYMBOL

With module.h being implicitly everywhere via device.h, the absence
of explicitly including something for EXPORT_SYMBOL went unnoticed.
Since we are heading to fix things up and clean module.h from the
device.h file, we need to explicitly include these files now.

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

arch/powerpc/kernel/crash.c

@@ -17,6 +17,7 @@
 #include <linux/reboot.h>
 #include <linux/kexec.h>
 #include <linux/bootmem.h>
+#include <linux/export.h>
 #include <linux/crash_dump.h>
 #include <linux/delay.h>
 #include <linux/elf.h>