kernel: Bump to 3.12.30

kernel: bcm2708: Eliminate i2s debugfs directory error
Qualify the two regmap ranges uses by bcm2708-i2s ('-i2s' and '-clk')
to avoid the name clash when registering debugfs entries.

kernel: Improve __copy_to_user and __copy_from_user performance
Provide a __copy_from_user that uses memcpy. On BCM2708, use
optimised memcpy/memmove/memcmp/memset implementations.

kernel: bcm2708-dmaengine: nobble peak throughput to prevend SD host lockups
Artificially throttling DMA throughput to/from the SD host prevents errors
seen on very high-spec UHS-1 cards.See: http://www.raspberrypi.org/forums/viewtopic.php?f=63&t=5057&start=275#p626694

firmware: dpi: Add options to alter dpi settings through dpi_output_format
See: http://www.raspberrypi.org/forums/viewtopic.php?f=100&t=86658&p=628061#p628061

firmware: arm_loader: Avoid gpioman spam when POWER_LOW is not defined