Some character devices may perform meaningful operations in their
implementation of close() -- a good example would be socfpga.c which
checks if the FPGA was programmed succesfully in it's close() method
-- so ignoring return value of this call may cause false positives in
checking exit status for success.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>