iopsys-bcm27xx: sync with upstream openwrt-21.02.1

iopsys-bcm27xx/Makefile

iopsys-bcm27xx/base-files/etc/board.d/02_network

iopsys-bcm27xx/base-files/etc/diag.sh

iopsys-bcm27xx/config/config

iopsys-bcm27xx/image/Makefile

iopsys-bcm27xx/iopsys-bcm2708/config-5.4

iopsys-bcm27xx/iopsys-bcm2709/config-5.4

iopsys-bcm27xx/iopsys-bcm2710/config-5.4

iopsys-bcm27xx/iopsys-bcm2711/config-5.4

iopsys-bcm27xx/iopsys-bcm2711/target.mk

iopsys-bcm27xx/modules.mk

iopsys-bcm27xx/modules/hwmon.mk

iopsys-bcm27xx/modules/i2c.mk

iopsys-bcm27xx/modules/other.mk

iopsys-bcm27xx/modules/sound.mk

iopsys-bcm27xx/modules/spi.mk

iopsys-bcm27xx/modules/video.mk

...maengine-bcm2835-Load-driver-early-and-support-lega.patch

...egister-the-clocks-early-during-the-boot-process-so.patch

...20-clk-bcm2835-Mark-used-PLLs-and-dividers-CRITICAL.patch