When ctrl-c is pressed then ctrlc() will return true until
ctrlc_handled() is called. This means that once ctrl-c is pressed every
NFS operation will fail until the upper layer calls ctrlc_handled().
When for example we are doing a 'ls -l' on an NFS directory then after
a ctrl-c press not the 'ls -l' aborts, but instead the retrieving of the
directory entries which is not what we want.

Simply do not call ctrlc() in the fs layer. the NFS timeout is 2 seconds
which we have to wait until we have a chance to abort.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>