ufshci: Introduce the ufshci(4) driver

This commit adds a storage driver that supports the Universal Flash
Storage Host Controller Interface (UFSHCI) on FreeBSD.

Universal Flash Storage (UFS) is a flash-based mobile storage device
that replaces eMMC, aiming for high performance with low power. The UFS
Host Controller Interface (UFSHCI) is the host side controller and
connects UFS device to a system bus, such as PCIe.

The code targets the latest standards:

• UFS 4.1: https://www.jedec.org/standards-documents/docs/jesd220g
• UFSHCI 4.1: https://www.jedec.org/standards-documents/docs/jesd223f

The ufshci(4) driver implements controller/device initialization,
interrupt, single-doorbell(SDB) queue based IO requests. Support for
multi-queue (MCQ) IO requests is planned for a later commit.

Implemented features:

• PCIe bus support
• legacy(INTx) Interrupt Handling
• UIC command support
• UTP Transfer Request (UTR) support
• UTP Task Management Request (UTMR) support
• single doorbell queue (SDB) with multiple queue depth
• SCSI command set support
• sysctl

Work in progress:

• multi-Circular Queue (per-CPU IO queues)
• MSI-X interrupt Support
• write booster
• write Protect
• Host Performance Booster (HPB)
• interrupt aggregation
• ARM based system bus support
• ufs-utils port

Tests were performed on QEMU and an Intel-based laptop.
Since QEMU has an emulated UFS device, I tested on QEMU.

How to test on QEMU:

1. Run QEMU $ qemu-system-x86_64 ... -device ufs -drive file=blk1g.bin,format=raw,if=none,id=luimg -device ufs-lu,drive=luimg,lun=0
2. Loading/unloading the ufshci module on QEMU $ kldload /usr/obj/usr/src/amd64.amd64/sys/modules/ufshci/ufshci.ko $ kldunload ufshci

Testing on real hardware:

• Samsung Galaxy Book S (Intel Lakefield) with UFS 3.0
• Lenovo duet 3 11ian8 (Intel N100) with UFS 2.1

Sponsored by: Samsung Electronics
Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D50370