hw/arm/aspeed: Split Tiogapass machine into a separate source file for cleanup

hw/arm/aspeed: Split Tiogapass machine into a separate source file for cleanup

This commit moves the Tiogapass BMC machine implementation out of
aspeed.c into a new dedicated file aspeed_ast2500_tiogapass.c.

To support splitting Tiogapass into a dedicated source file,
a new TIOGAPASS_BMC_HW_STRAP1 macro is added as a copy of
AST2500_EVB_HW_STRAP1.

The change follows the ongoing effort to modularize Aspeed platform
support by splitting each machine definition into its own source file.
This makes aspeed.c cleaner, easier to maintain, and simplifies
future feature additions or refactoring for individual machines.

Key updates include:
- Removed tiogapass_bmc_i2c_init() and its FRU data from aspeed.c
and aspeed_eeprom.c.
- Removed Tiogapass type registration from aspeed_machine_types[].
- Added new source file aspeed_ast2500_tiogapass.c to meson.build.
- Removed unused Tiogapass FRUID declarations from aspeed_eeprom.h.

No functional changes.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Link: https://lore.kernel.org/qemu-devel/20251104031325.146374-8-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>