[PATCH v2] kselftest/devices/probe: Fix SyntaxWarning in regex strings for Python 3

[Alessandro Zanni <alessandro.zanni87@gmail.com>]

Insert raw strings to prevent Python3 from interpreting string literals as Unicode strings
and, consequently, '\d' as an invalid escaped sequence.
Avoid the 'SyntaxWarning: invalid escape sequence '\d'' warning for Python versions greater than 3.6.

Fixes: dacf1d7a78bf ("kselftest: Add test to verify probe of devices from discoverable buses")

Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Signed-off-by: Alessandro Zanni <alessandro.zanni87@gmail.com>
---

Notes:
    v2: Imperative mode description for the inserted changes, added previous commit tag fixed by this patch

 .../selftests/devices/probe/test_discoverable_devices.py      | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/devices/probe/test_discoverable_devices.py b/tools/testing/selftests/devices/probe/test_discoverable_devices.py
index d94a74b8a054..d7a2bb91c807 100755
--- a/tools/testing/selftests/devices/probe/test_discoverable_devices.py
+++ b/tools/testing/selftests/devices/probe/test_discoverable_devices.py
@@ -45,7 +45,7 @@ def find_pci_controller_dirs():
 
 
 def find_usb_controller_dirs():
-    usb_controller_sysfs_dir = "usb[\d]+"
+    usb_controller_sysfs_dir = r"usb[\d]+"
 
     dir_regex = re.compile(usb_controller_sysfs_dir)
     for d in os.scandir(sysfs_usb_devices):
@@ -91,7 +91,7 @@ def get_acpi_uid(sysfs_dev_dir):
 
 
 def get_usb_version(sysfs_dev_dir):
-    re_usb_version = re.compile("PRODUCT=.*/(\d)/.*")
+    re_usb_version = re.compile(r"PRODUCT=.*/(\d)/.*")
     with open(os.path.join(sysfs_dev_dir, "uevent")) as f:
         return int(re_usb_version.search(f.read()).group(1))
 
-- 
2.43.0