6625e5aad4
Upstream dts for allwinner will require a syscon driver, since the emac node coming in 4.15 will be using xref to /soc/syscon for configuring the emac clock. Add a generic syscon driver to attach to /soc/syscon for use by if_awg, providing basic read/write functionality to consumers. syscon driver will also be used by arm64 at least for A64+H5 emac/if_awg. Written by: mmel Reviewed by: manu Differential Revision: https://reviews.freebsd.org/D13295