Linux 6.0 adds a constant ADDRB, a termios c_cflag bit, to its
include/uapi/asm-generic/termbits-common.h.
Add it accordingly to glibc's bits/termios-c_cflag.h headers. As
other constants in these headers are generally in octal, I converted
the value to octal to match. As ADDRB isn't in a POSIX-reserved
namespace, I made it conditional on __USE_MISC.
Tested for x86_64.
b87a70e5e2