idle.2012.09.18b contains additional RCU changes in support of Frederic's
adaptive dynticks and also fixes architectures for which RCU no
longer considered the idle loop to be a quiescent state due to
earlier adaptive-dynticks changes. Affected architectures are
alpha, cris, frv, h8300, m32r, m68k, mn10300, parisc, score,
xtensa, and ia64.