util/lint: Fix license header regex

A trailing "|" at the end of the regex added a zero length alternative
match, causing all files to match and be filtered out. This was causing
`make lint-stable` to ignore all missing license headers, preventing the
pre-commit git hook and Jenkins from detecting these. Also, a missing
"|" separator between cmos.default and .apcb would cause those files to
be unintentionally scanned.

Change-Id: I70cc3a5adf7edee059883cd3cbe02029776b02ef
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81422
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

util/lint/lint-000-license-headers

@@ -67,8 +67,8 @@ _shipped$|\
 \.spd|\
 config|\
 cmos\.layout|\
-cmos\.default\
-\.apcb$|\
+cmos\.default|\
+\.apcb$\
 "
 
 #space separated list of directories to test