mmc: sdhci-of-aspeed: add inversion signal presence

Add read_l callback in sdhci_ops with flipping of SDHCI_CARD_PRESENT
bit in case of inverted card detection signal.

Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>