modules: add default loader hook implementations

The module loader code allows architectures to hook into the code by
providing a small number of entry points that each arch must implement.
This patch provides __weakly linked generic implementations of these
entry points for architectures that don't need to do anything special.

Signed-off-by: Jonas Bonn <jonas@southpole.se>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
block: add REQ_URGENT to request flags
usb: MTP fix
governor: Fix SLEEPY governor
asm: Add idle
governor: SLEEPY fix suspend freq
ramdisk: Remove journal removal code. Fix OOM.
defconfig: update and fixes