ddr: altera: Add uibssm mailbox support for Agilex7 M-series with HBM

ddr: altera: Add uibssm mailbox support for Agilex7 M-series with HBM

Add uibssm mailbox driver for Agilex7 M-series. HPS will interact with UIB
and HBM subsystem through software defined mailbox interface.
HPS can retrieve HBM memory interface calibration status, UIB
configuration, memory interfae configuration, trigger calibration and etc
with the list of supported mailbox command type and opcode.

Signed-off-by: Tingting Meng <tingting.meng@altera.com>
Signed-off-by: Alif Zakuan Yuslaimi <alif.zakuan.yuslaimi@altera.com>
Reviewed-by: Tien Fong Chee <tien.fong.chee@altera.com>