misc: genwqe: card_base: Remove set but unused variable 'rc'

misc: genwqe: card_base: Remove set but unused variable 'rc'

Variable 'rc' hasn't been checked since the driver's inception
in 2013.  If it hasn't caused any issues since then, it's unlikely
to in the future.  Let's take it out for now.

Fixes the following W=1 kernel build warning(s):

 drivers/misc/genwqe/card_base.c: In function ‘genwqe_health_check_stop’:
 /home/lee/projects/linux/kernel/drivers/misc/genwqe/card_base.c:1046:6: warning: variable ‘rc’ set but not used [-Wunused-but-set-variable]
 1046 | int rc;
 | ^~

Cc: Michael Jung <mijung@gmx.net>
Cc: Michael Ruettger <michael@ibmra.de>
Cc: Frank Haverkamp <haver@linux.ibm.com>
Cc: Joerg-Stephan Vogt <jsvogt@de.ibm.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Frank Haverkamp <haver@linux.ibm.com>
Link: https://lore.kernel.org/r/20200701085853.164358-17-lee.jones@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>