hw/sd: sdhci: Support version 4 ADMA 64-bit addressing

The Cadence Linux driver enables version 4 mode and 64-bit addressing in
Host Control 2 but retains the ADMA2 encoding in Host Control 1. QEMU
treats the transfer as 32-bit ADMA and uses 12-byte descriptors because
it only decodes Host Control 1.

Resolve the DMA type from both control registers and use 16-byte version
4 descriptors. Preserve the legacy 12-byte ADMA2 64-bit format when
version 4 mode is disabled.

Signed-off-by: Bin Meng <bin.meng@processmission.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Message-ID: <20260723151853.2143177-11-bin.meng@processmission.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>