ath79: add support for linux 4.19

The following patches are dropped because they are merged upstream:
-0001-tty-serial-drop-QCA-pecific-SoC-symbols.patch
-0006-usb-drop-deprecated-symbols.patch
-0009-MIPS-ath79-add-lots-of-missing-registers.patch
-0010-MIPS-ath79-add-support-for-QCA953x-QCA956x-TP9343.patch
-0014-MIPS-ath79-finetune-cpu-overrides.patch
-0015-MIPS-ath79-enable-uart-during-early_prink.patch
-0016-MIPS-ath79-get-PCIe-controller-out-of-reset.patch

This patch is dropped due to the introduction of spi-mem framework:
-461-spi-ath79-add-fast-flash-read.patch

Thank to Michael Marley @mamarley for his work on this patch:
-910-unaligned_access_hacks.patch

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
[synchronized kernel config with make kernel_oldconfig]
Signed-off-by: Petr Štetiar <ynezz@true.cz>