scripts: checkpatch: Revert dt-binding vendor prefix check regex change
scripts: checkpatch: Revert dt-binding vendor prefix check regex change

This commit reverts the device tree binding vendor prefix check regular
expression change that was introduced by the following commit:
5b10fac97efdb444b49f5e3c3ac16048ce8661c6

The changed regular expression fails to detect the correctly specified
vendor prefixes in the `vendor-prefixes.txt`.

Signed-off-by: Stephanos Ioannidis <dc76e9f0c0006e8f919e0c515c66dbba3982f785@stephanos.io>

Vudentz/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,nashif/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,galak/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr