ath79-generic: drop TP-Link RE450 and RE355 #312

Job	Run time
generate_target_matrix	5s
build_firmware (ath79-generic)	2h 31m 21s
build_firmware (ath79-mikrotik)	1h 53m 18s
build_firmware (ath79-nand)	1h 52m 12s
build_firmware (bcm27xx-bcm2708)	2h 3m 51s
build_firmware (bcm27xx-bcm2709)	2h 39m 12s
build_firmware (bcm27xx-bcm2710)	2h 48m 21s
build_firmware (bcm27xx-bcm2711)	2h 6m 27s
build_firmware (ipq40xx-generic)	2h 26m 48s
build_firmware (ipq40xx-mikrotik)	2h 1m 57s
build_firmware (ipq806x-generic)	2h 29m 38s
build_firmware (lantiq-xrx200)	2h 3m 51s
build_firmware (lantiq-xway)	1h 58m 27s
build_firmware (mediatek-mt7622)	2h 10m 0s
build_firmware (mpc85xx-p1010)	2h 26m 30s
build_firmware (mpc85xx-p1020)	2h 19m 56s
build_firmware (mvebu-cortexa9)	2h 18m 30s
build_firmware (ramips-mt7620)	1h 57m 19s
build_firmware (ramips-mt7621)	1h 57m 34s
build_firmware (ramips-mt76x8)	1h 54m 41s
build_firmware (rockchip-armv8)	2h 9m 6s
build_firmware (sunxi-cortexa7)	1h 45m 6s
build_firmware (x86-64)	2h 32m 9s
build_firmware (x86-generic)	2h 35m 32s
build_firmware (x86-geode)	2h 5m 35s
build_firmware (x86-legacy)	2h 3m 37s
create_release	0s
	2d 7h 11m 3s

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