mmc: core: Allows to override the timeout value for ioctl() path

Occasionally, user-land applications initiate longer timeout values for certain commands
through ioctl() system call. But so far we are still using a fixed timeout of 10 seconds
in mmc_poll_for_busy() on the ioctl() path, even if a custom timeout is specified in the
userspace application. This patch allows custom timeout values to override this default
timeout values on the ioctl path.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Bean Huo <beanhuo@micron.com>
Acked-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20220423221623.1074556-3-huobean@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>