docs: driver-api: add remaining converted dirs to it

There are a number of driver-specific descriptions that contain a
mix of userspace and kernelspace documentation. Just like we did
with other similar subsystems, add them at the driver-api
groupset, but don't move the directories.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Documentation/driver-api/index.rst

@@ -83,6 +83,8 @@ available subsections can be seen below.
    ntb
    nvmem
    parport-lowlevel
+   pps
+   ptp
    pti_intel_mid
    pwm
    rfkill

Documentation/driver-api/pps.rst

-:orphan:
+.. SPDX-License-Identifier: GPL-2.0
 
 ======================
 PPS - Pulse Per Second

Documentation/driver-api/ptp.rst

-:orphan:
+.. SPDX-License-Identifier: GPL-2.0
 
 ===========================================
 PTP hardware clock infrastructure for Linux

Documentation/index.rst

@@ -110,6 +110,9 @@ needed).
    bpf/index
    usb/index
    misc-devices/index
+   mic/index
+   phy/samsung-usb2
+   scheduler/index
 
 Architecture-specific documentation
 -----------------------------------

Documentation/mic/index.rst

-:orphan:
-
 =============================================
 Intel Many Integrated Core (MIC) architecture
 =============================================

Documentation/phy/samsung-usb2.rst

-:orphan:
-
 ====================================
 Samsung USB 2.0 PHY adaptation layer
 ====================================

Documentation/scheduler/index.rst

-:orphan:
-
 ===============
 Linux Scheduler
 ===============