sandbox: Enable bitrev library build

Imply CONFIG_BITREVERSE for Sandbox.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>
Reviewed-by: NSimon Glass <sjg@chromium.org>

arch/Kconfig

@@ -78,6 +78,7 @@ config SANDBOX
 	select LZO
 	select SPI
 	select SUPPORT_OF_CONTROL
+	imply BITREVERSE
 	imply CMD_DM
 	imply CMD_GETTIME
 	imply CMD_HASH