pinctrl: qcom: lpass-lpi: Remove unused member in struct lpi_pingroup

The group is not used anywhere, remove it. And if needed, it should be
struct pingroup anyway.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231129161459.1002323-3-andriy.shevchenko@linux.intel.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>