ath79: fix I2C pins on GL-AR750

ath79: fix I2C pins on GL-AR750

Change I2C pin flags to GPIO_ACTIVE_HIGH and change SDA to GPIO1.

On my late production GL-AR750 (purchased 2024):
SCL = GPIO16
SDA = GPIO1

Bug report:
I2C bus doesn't work in GL-AR750
https://github.com/openwrt/openwrt/issues/16319

Signed-off-by: Ryan Salsbury <ryanrs@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16406
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit 2e626ae2d2488f2d3708d3aed57eea7a1402f00e)
Signed-off-by: Ryan Salsbury <ryanrs@gmail.com>
Link: https://github.com/openwrt/openwrt/pull/16446
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>