linux-postmarketos-exynos5: update to 6.6.59

Two main changes apart from rebase and config sync:

• Fix broken usb networking by making CONFIG_USB_CDC_COMPOSITE builtin (by @Eisenbahnfan)
• Add mainline support for exynos5420-n2awifi (by @Eisenbahnfan)

Tested on odroid-xu4 and samsung-klimtlte. I planned to test on samsung-manta as well, but seems battery is too deep-discharged on that one.. Since this is essentially a minor update (6.6.41 -> 6.6.59) I am not too worried and think that testing on two devices should be enough.