ASoC: aw88395: Fix kernel panic caused by invalid GPIO error pointer

ASoC: aw88395: Fix kernel panic caused by invalid GPIO error pointer

In aw88395_i2c_probe(), if `devm_gpiod_get_optional()` fails, it returns
an ERR_PTR() error pointer. The current code only prints a message and
continues execution, leaving `aw88395->reset_gpio` as an invalid pointer.

Later, in `aw88395_hw_reset()`, this invalid pointer is passed to
`gpiod_set_value_cansleep()`, which dereferences it and causes a kernel
panic.

For optional GPIOs, `devm_gpiod_get_optional()` returns NULL if the GPIO
is not defined in the DT, which is safe. If it returns an ERR_PTR, it
means a real error occurred (e.g., -EPROBE_DEFER) and the probe must be
aborted.

Also, since the GPIO is optional, remove the dev_err() log in
aw88395_hw_reset() when the GPIO is missing to match the optional
semantics. This also fixes a potential NULL pointer dereference as
aw_pa is not initialized when aw88395_hw_reset() is called.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
Link: https://patch.msgid.link/20260428023408.46420-1-wangdich9700@163.com
Signed-off-by: Mark Brown <broonie@kernel.org>