Update to v6.0 kernel headers.

Kernel headers coming from:

Git: https://android.googlesource.com/kernel/common/
Branch: android-mainline
Tag: android-mainline-6.0

Test: Boots on coral.
Test: Bionic unit tests pass.
Change-Id: I282de83f23b432bef58214108a93700bdadddf0f
diff --git a/libc/kernel/uapi/asm-generic/termbits-common.h b/libc/kernel/uapi/asm-generic/termbits-common.h
index c67f21d..281eee8 100644
--- a/libc/kernel/uapi/asm-generic/termbits-common.h
+++ b/libc/kernel/uapi/asm-generic/termbits-common.h
@@ -54,6 +54,7 @@
 #define B38400 0x0000000f
 #define EXTA B19200
 #define EXTB B38400
+#define ADDRB 0x20000000
 #define CMSPAR 0x40000000
 #define CRTSCTS 0x80000000
 #define IBSHIFT 16