snd_uaudio.4: Rework SYNOPSIS, add HARDWARE, SPDX

+ Rework synopsis for consistency, adding sysctls
+ Add a HARDWARE section for HW relnotes
+ tag SPDX

MFC after:		3 days
Reviewed by:		christos, pauamma
Differential Revision:	https://reviews.freebsd.org/D51240

share/man/man4/snd_uaudio.4

@@ -1,3 +1,6 @@
+.\"
+.\" SPDX-License-Identifier: BSD-2-Clause
+.\"
 .\" $NetBSD: uaudio.4,v 1.15 2002/02/12 19:53:57 jdolecek Exp $
 .\"
 .\" Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -27,32 +30,30 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd February 15, 2025
+.Dd July 17, 2025
 .Dt SND_UAUDIO 4
 .Os
 .Sh NAME
 .Nm snd_uaudio
 .Nd USB audio and MIDI device driver
 .Sh SYNOPSIS
-To compile this driver into the kernel, place the following lines in your
-kernel configuration file:
-.Bd -ragged -offset indent
 .Cd "device sound"
 .Cd "device usb"
 .Cd "device snd_uaudio"
-.Ed
 .Pp
-Alternatively, to load the driver as a module at boot time, place the
-following line in
-.Xr loader.conf 5 :
-.Bd -literal -offset indent
-snd_uaudio_load="YES"
-.Ed
+In
+.Xr rc.conf 5 :
+.Cd kld_list="snd_uaudio"
+.Pp
+In
+.Xr sysctl.conf 5 :
+.Cd hw.usb.uaudio.buffer_ms
+.Cd hw.usb.uaudio.default_bits
+.Cd hw.usb.uaudio.default_channels
+.Cd hw.usb.uaudio.default_rate
+.Cd hw.usb.uaudio.handle_hid
+.Cd hw.usb.uaudio.debug
 .Sh DESCRIPTION
-The
-.Nm
-driver provides support for USB audio class devices and USB MIDI class devices.
-.Pp
 A USB audio device consists of a number of components: input terminals (e.g.\&
 USB digital input), output terminals (e.g.\& speakers), and a number of units
 in between (e.g.\& volume control).
@@ -68,6 +69,11 @@ sample rate and sample size.
 Refer to the
 .Ql USB Audio Class Specification
 for more information.
+.Sh HARDWARE
+The
+.Nm
+driver provides support for USB audio class devices and
+USB MIDI class devices.
 .Sh SYSCTL VARIABLES
 The following settings can be entered at the
 .Xr loader 8