Input: charlieplex_keypad - check gpiod_direction_output() return value

charlieplex_keypad_scan_line() currently ignores the return value of
gpiod_direction_output() when setting the active output line for scanning.

If setting the GPIO direction fails (e.g. on I2C/SPI GPIO expanders or
hardware errors), the function continues to sleep and read input values
from an improperly configured GPIO line.

Fix this by capturing the return value of gpiod_direction_output() and
returning the error code immediately if it fails.

Fixes: 2ca45e57ea02 ("Input: charlieplex_keypad - add GPIO charlieplex keypad")
Signed-off-by: Surendra Singh Chouhan <kr494167@gmail.com>
Link: https://patch.msgid.link/20260723022943.9337-1-kr494167@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>