hw/arm/aspeed: Split QCOM Firework machine into a separate source file for maintainab...

hw/arm/aspeed: Split QCOM Firework machine into a separate source file for maintainability

This commit moves the QCOM Firework BMC machine implementation out of
aspeed.c into a new standalone file aspeed_ast2600_qcom-firework.c.

This refactor continues the modularization effort for Aspeed platform support,
placing each board’s logic in its own dedicated source file. It improves
maintainability, readability, and simplifies future development for new
platforms without cluttering aspeed.c.

Key updates include:
- Removed qcom_dc_scm_firework_i2c_init() and its Firework-specific devices
  from aspeed.c.
- Removed aspeed_machine_qcom_firework_class_init() and its type registration
  ("qcom-firework-bmc") from aspeed_machine_types[].
- Added new source file aspeed_ast2600_qcom-firework.c containing the
  Firework-specific initialization and machine class definition.
- Updated hw/arm/meson.build to include aspeed_ast2600_qcom-firework.c.
- Cleaned up all Firework-specific code from aspeed.c.
- Renamed `QCOM_DC_SCM_V1_BMC_HW_STRAP1` to
  `QCOM_DC_SCM_FIREWORK_BMC_HW_STRAP1` to avoid dependency conflicts with
  other QCOM DC-SCM machines.

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/20251104031325.146374-22-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>