mmc: socfpga_dw_mmc: Restore legacy clkmgr address retrieval

mmc: socfpga_dw_mmc: Restore legacy clkmgr address retrieval

Restore legacy implementation of retrieving clkmgr base address from
mach-socfpga/misc.c driver for our legacy devices.

Excluding Agilex7/7M from this implementation as these devices' clock
driver is already following clock driver model and is supporting
enable/disable APIs.

The legacy devices' clock driver will have to be refactored to support
driver model which enables us to support enable/disable APIs for these
devices.

Fixes: ab27182cac8f ("mmc: socfpga_dw_mmc: Enable/disable SDMMC clock via API")

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