kernel: bump 6.12 to 6.12.56

kernel: bump 6.12 to 6.12.56

Changelog: https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.12.56

Removed upstreamed:
- airoha/patches-6.12/028-v6.13-spi-airoha-do-not-keep-tx-rx-dma-buffer-always-mappe.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.12.56&id=ad00df9ee321e87639a740e6e372f11bfe5af52c
- airoha/patches-6.12/029-01-spi-airoha-return-an-error-for-continuous-mode-di.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/drivers/spi?h=v6.12.56&id=f5dc5baa5b04ceb0fca2460bc2863921f0e7ede5
- airoha/patches-6.12/029-03-spi-airoha-add-support-of-dual-quad-wires-spi-mod.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.12.56&id=182221d35c1427630ea6d9de9953c2280848c851
- airoha/patches-6.12/029-05-spi-airoha-switch-back-to-non-dma-mode-in-the-cas.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.12.56&id=8063828625359826316c5a1885e9ea341bbdb1b3
- airoha/patches-6.12/029-06-spi-airoha-fix-reading-writing-of-flashes-with-mo.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.12.56&id=4e9a2d592d91b902f918158c1049eef19f9cce90
- mediatek/patches-6.12/810-tty-serial-8250_mtk-enable-baud-clock.patch
  https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=v6.12.56&id=7cbf5ed24a26d4d80dcc19eb2259fdb9b179d5cf

All other patches automatically rebased.

Build system: x86/64
Build-tested: mediatek/filogic
Run-tested: mediatek/filogic

Signed-off-by: Edoardo Pinci <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/20589
Signed-off-by: Hauke Mehrtens <[email protected]>