i2c: gpio: remove error checks with debugfs

i2c: gpio: remove error checks with debugfs

debugfs can handle error pointers in subsequent calls. So, remove the
error checks as suggested by kerneldoc of this function.

Reported-by: Minjie Du <duminjie@vivo.com>
Closes: http://patchwork.ozlabs.org/project/linux-i2c/patch/20230713101829.15548-1-duminjie@vivo.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Wolfram Sang <wsa@kernel.org>