mmc: sunxi: Fix misuse of gpio_direction_input()

mmc: sunxi: Fix misuse of gpio_direction_input()

It does not make sense to make gpio_direction_input() return the gpio input
status. The return value of gpio_direction_input() is inconsistent if
CONFIG_DM_GPIO is defined.
And we don't need to call gpio_direction_input() int sunxi_mmc_getcd().
Just init the gpio once in mmc_resource_init() is enough.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Ian Campbell <ijc@hellion.org.uk>