greybus: firmware: Fix spelling mistake

s/directly/directory :)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Documentation/firmware/firmware-management

@@ -185,6 +185,6 @@ mtd0    mtd0ro
 Sample Application
 ------------------
 
-The current directly also provides a firmware.c test application, which can be
+The current directory also provides a firmware.c test application, which can be
 referenced while developing userspace application to talk to firmware-management
 protocol.