ufshci: install the ioctl header

The passthrough ioctl has a userland ABI header, but nothing installed
it. A program that wanted to use the ioctl had to copy the headers out
of the source tree by hand.

Install ufshci.h and ufshci_ioctl.h under /usr/include/dev/ufshci, the
way nvme installs nvme.h. The ioctl header pulls in ufshci.h, so both
go. Add the directory to the include mtree so installworld creates it.

Reviewed by:	imp (mentor)
Sponsored by:	Samsung Electronics
Differential Revision:	https://reviews.freebsd.org/D59560

etc/mtree/BSD.include.dist

@@ -261,6 +261,8 @@
         ..
         tcp_log
         ..
+        ufshci
+        ..
         usb
         ..
         veriexec

include/Makefile

@@ -198,6 +198,11 @@ NVMFDIR=	${INCLUDEDIR}/dev/nvmf
 PCI=		pcireg.h
 PCIDIR=		${INCLUDEDIR}/dev/pci
 
+.PATH: ${SRCTOP}/sys/dev/ufshci
+UFSHCI=		ufshci.h \
+		ufshci_ioctl.h
+UFSHCIDIR=	${INCLUDEDIR}/dev/ufshci
+
 .PATH: ${SRCTOP}/sys/dev/veriexec
 VERIEXEC=	veriexec_ioctl.h
 VERIEXECDIR=	${INCLUDEDIR}/dev/veriexec
@@ -273,6 +278,7 @@ INCSGROUPS=	INCS \
 		RPC \
 		SECAUDIT \
 		TEKEN \
+		UFSHCI \
 		VERIEXEC \
 		WG