ARM: dts: bcm283x: Fix probing of bcm2835-i2s

Since 517e7a15 ("ASoC: bcm2835: move to use the clock framework")
the bcm2835-i2s requires a clock as DT property. Unfortunately
the necessary DT change has never been applied. While we are at it
also fix the first PCM register range to cover the PCM_GRAY register.

Fixes: 517e7a15 ("ASoC: bcm2835: move to use the clock framework")
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Eric Anholt <eric@anholt.net>