Revert "net: flow: Prevent bringing up new CPUs during per-CPU initialization"

This reverts commit 6c0fceb5db0e7358b50ec7684e45cb57ed8cc816.
Revert "sync: don't block the flusher thread waiting on IO"

This reverts commit b0326f8980ab400270ca28c4a013221f6eafd2e5.
Revert "cris: convert ffs from an object-like macro to a function-like macro"

This reverts commit dd5a8b531c8c906ab60300c753d4a33cb71f32b3.