Input: synaptics - LEN205b (ThinkPad T490) works with synaptics_intertouch=1

Hello,

Per the kernel message, reporting that the touchpad below works
correctly over SMBus/RMI4 with psmouse.synaptics_intertouch=1.

Machine: Lenovo ThinkPad T490
PNP ID: LEN205b PNP0f13
Distro: Fedora 44
Kernel: 7.2.5-200.fc44.x86_64

dmesg before the change:
psmouse serio1: synaptics: Your touchpad (PNP: LEN205b PNP0f13) says
it can support a different bus. If i2c-hid and hid-rmi are not used,
you might want to try setting psmouse.synaptics_intertouch to 1 and
report this to linux-input@vger.kernel.org.
psmouse serio1: synaptics: Touchpad model: 1, fw: 10.32, id: 0x1e2a1,
caps: 0xf014a3/0x940300/0x12e800/0x500000, board id: 3471, fw id:
3972349

Results with intertouch enabled:
- Touchpad and TrackPoint both work
- Multi-finger gestures are much more reliable than under PS/2
- Both devices still work after suspend/resume

Please consider adding LEN205b to smbus_pnp_ids in
drivers/input/mouse/synaptics.c.

Thanks,
John