feat(altera): add Agilex72 platform base enablement

Introduce Agilex72 BL2/BL31 platform enablement including GICv4,
A720/A520 SMP product naming, Simics bring-up fixes, direct SD boot,
v9 GPPLL clock-manager FSBL bring-up, and MCSR mailbox support
required for HPS-SDM communication.

Also align the shared Altera NAND init API to nand_init(void) and
update the Agilex3 call site so PLAT=agilex3 remains buildable.
PSCI now uses shared PWRMGR_* aliases; wire those (and cache
headers) into Agilex3 plat_def so existing platforms still build.
Guard Agilex3 cache prototypes with __ASSEMBLER__ so plat_def can be
included from assembly.
Keep Agilex3 ncore CCU bases and noc_fw programming, and the
upstream combo-PHY SDMMC DFI select. Agilex72 uses its own CCU
map and handoff-based DFI selection.

Address review feedback on this change:
- rename plat_flash_* to altera_plat_flash_*
- drop commented-out / unused bring-up stubs (incl. empty mmc stub)
- switch Agilex72 to USE_GIC_DRIVER=3
- rewrite cache helpers in C using arch helpers
- use utils_def EXTRACT/MASK for IOSSM fields
- trim commented system-manager defines; clarify PSCI vs RMR_EL3
- fix A720/A520 comments, enable FEATURE_DETECTION, drop unused evals
- add Agilex72 code owner in docs/about/maintainers.rst
- fix include order in bl31_plat_setup.c for static checks
- cast EXTRACT() log args to fix -Werror=format on aarch64
- restore Linux BL33/DTB build defines removed during review cleanup
- provide the GICv3 MPIDR-to-core-position topology hook
- define the default UART and fix release RESET_TO_BL31 compilation
- drop redundant eval around assert_boolean/add_defines calls
- remove stale bring-up markers and make the memcpy include explicit
- drop leftover commented-out stubs; silence checkpatch long-line warning
- preserve the upper CLUSTERECTLR_EL1 bits when masking bit 14
- drop a dead ddr init prototype and duplicate register defines
- rename the copied AGX5_ pinmux symbols to AGX72_

xSPI flash boot and Config DMA remain deferred to a follow-up commit.

Change-Id: If7b51026af7f685f51aad5ed0140240afdd7f721
Signed-off-by: Jit Loon Lim <jit.loon.lim@altera.com>
Signed-off-by: Poh San Ng <poh.san.ng@altera.com>
Signed-off-by: Bryan Chan Jia Ching <bryan.chan@altera.com>
Signed-off-by: Yong Zi Hao <zi.hao.yong@altera.com>