staging: echo: move to drivers/misc/

The code is clean, there are users of it, so it doesn't belong in
staging anymore, move it to drivers/misc/.

Cc: Steve Underwood <steveu@coppice.org>
Cc: David Rowe <david@rowetel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 99b9424..7eb4b69 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -54,3 +54,4 @@
 obj-$(CONFIG_SRAM)		+= sram.o
 obj-y				+= mic/
 obj-$(CONFIG_GENWQE)		+= genwqe/
+obj-$(CONFIG_ECHO)		+= echo/