binderfs: binderfs_test: remove unused variable

The variable "wret" is never referenced in the code, just remove it.

Signed-off-by: Ba Jing <bajing@cmss.chinamobile.com>
Link: https://lore.kernel.org/r/20240903041620.10812-1-bajing@cmss.chinamobile.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>