main/linux-postmarketos-qcom-msm8974: upgrade to 5.13.0

Should work same as before.

Slightly tweaked kernel config options:

• default cpufreq governor is now "conservative" instead of "performance", which should be better for devices running on battery. Not that it matters, MSM8974 does not have cpufreq support anyway.
• enabled CONFIG_ARM_QCOM_SPM_CPUIDLE, which was missing! At least some cpuide is better than none at all.
• 2 missing options for nftables: CONFIG_IP6_NF_FILTER, CONFIG_IP6_NF_TARGET_REJECT
• few missing options for wg-quick: CONFIG_IPV6_MULTIPLE_TABLES, CONFIG_IP_MULTIPLE_TABLES, CONFIG_IP6_NF_RAW, CONFIG_IP_NF_RAW

WWAN subsystem is not enabled.

BAM-DMUX upgraded to version "v3" (subnode of modem remoteproc)

Mark kernel package as supporting anbox, containers (in addition to nftables)

This is mostly a simple rebase.

• samsung-klte
• fairphone-fp2 ( @z3ntu ?)
• lg-hammerhead ( @JuniorJPDJ ?)
• oneplus-bacon ( @Kanedias ?)
• sony-castor-windy ( @julianuu ) (for future reference, so I remember)