hw/sd/sdcard: Make sd_data_ready() static

sd_data_ready() belongs to the legacy API. As its last user has
been converted to the SDBus API, make it static.

Reviewed-by: Alistair Francis <alistair.francis@xilinx.com>
Message-Id: <20180216022933.10945-7-f4bug@amsat.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
2 files changed