linux-wandboard

[AVR32] Warn, don't BUG if clk_disable is called too many times

Print a helpful warning along with a stack dump if clk_disable is
called on a already-disabled clock. Remove the BUG_ON().

Extracted from a patch by David Brownell.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>