kconfigcheck: require NULL_TTY support (MR 6087)

The null TTY driver provides a proper (dummy) TTY interface when
console=null is set on the kernel cmdline. This fixes certain
applications which don't correctly handle read() immediately returning
with 0 bytes (e.g. busybox syslogd).

Most normal EFI devices don't boot with console=null and as such there
are various foot-guns littered all over Linux userspace and even in our
own initramfs. However some android devices even enforce console=null,
so it's something we have to deal with.

NULL_TTY should reduce the chance of folks running into strange problems
because of this.

Signed-off-by: Caleb Connolly <caleb@postmarketos.org>

kconfigcheck.toml

@@ -73,6 +73,10 @@ SAMSUNG_TUI = false
 TZDEV = false
 ["category:default"."<5.2.0"."armhf armv7 x86"]
 LBDAF = true
+["category:default".">=5.2.0"."all"]
+# Provide a proper dummy null console to improve compatibility
+# on devices that like to coerce console=null
+NULL_TTY = true
 ["category:default".">=5.19.0"."all"]
 FW_LOADER_COMPRESS_ZSTD = true