hw/misc/aspeed_sbc: Add CAMP2 support for OTP data reads

hw/misc/aspeed_sbc: Add CAMP2 support for OTP data reads

The OTP space contains three types of entries: data, conf, and strap.
Data entries consist of two DWORDs, while the other types contain
only one DWORD. This change adds the R_CAMP2 register (0x024 / 4) to
store the second DWORD when reading from the OTP data region.

With this enhancement, OTP reads now correctly return both DWORDs for
data entries via the CAMP registers, along with improved address
validation and error handling.

Signed-off-by: Kane-Chen-AS <kane_chen@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20250812094011.2617526-8-kane_chen@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>