iio:adc:berlin2-adc: enable interrupts with mutex locked
iio:adc:berlin2-adc: enable interrupts with mutex locked

Move the call to enable channel interrupts into its _read() function to
have it protected by a mutex. This ensures that only one channel is
sampled at a time.

Signed-off-by: Hartmut Knaack <4bccb8448924141fc676c25eb657b52ee47a361d@gmx.de>
Signed-off-by: Jonathan Cameron <09f65b71b7655725897b2fd41a09a0cefe2e1ace@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs