hw/sd/sdhci: Do not force sdhci_mmio_*_ops onto all SD controllers

hw/sd/sdhci: Do not force sdhci_mmio_*_ops onto all SD controllers

Since commit c0a55a0c9da2 "hw/sd/sdhci: Support big endian SD host controller
interfaces" sdhci_common_realize() forces all SD card controllers to use either
sdhci_mmio_le_ops or sdhci_mmio_be_ops, depending on the "endianness" property.
However, there are device models which use different MMIO ops: TYPE_IMX_USDHC
uses usdhc_mmio_ops and TYPE_S3C_SDHCI uses sdhci_s3c_mmio_ops.

Forcing sdhci_mmio_le_ops breaks SD card handling on the "sabrelite" board, for
example. Fix this by defaulting the io_ops to little endian and switch to big
endian in sdhci_common_realize() only if there is a matchig big endian variant
available.

Fixes: c0a55a0c9da2 ("hw/sd/sdhci: Support big endian SD host controller
interfaces")

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Message-Id: <20230709080950.92489-1-shentey@gmail.com>
(cherry picked from commit 3b830790151ff231531ef2595793e387dd154efb)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>