Don't deny smartcards in usb-policy.conf

Backport of 651a7b9.

Removing this device class from the USB config would let admins
configure VMs for digital signing purposes.

These devices are also not very useful in Dom0.

Signed-off-by: Tu Dinh <ngoc-tu.dinh@vates.tech>

Author: dinhngtu

scripts/usb-policy.conf

@@ -20,7 +20,6 @@ ALLOW:vid=056a pid=00fb class=03 # Wacom DTU tablet
 DENY: class=03 subclass=01 prot=01 # HID Boot keyboards
 DENY: class=03 subclass=01 prot=02 # HID Boot mice
 DENY: class=0a # CDC-Data
-DENY: class=0b # Smartcard
 DENY: class=e0 # Wireless controller
 DENY: class=ef subclass=04 # Miscellaneous network devices
 ALLOW: # Otherwise allow everything else