powerlog: fix "SusbError is not defined"

SusbError is not defined in powerlog.py
This change raises Exception type instead.

BUG=none
BRANCH=none
TEST=powerlog [..] -A=garbage
  => raises Exception: ('Power', 'USB device(garbage) not found')

Change-Id: I8167a50796fec81f0fdf84d58e2e565f574c4f51
Signed-off-by: David Herrig <dherrig@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2324868
Reviewed-by: Nick Sanders <nsanders@chromium.org>
Reviewed-by: Mengqi Guo <mqg@chromium.org>

extra/usb_power/powerlog.py

@@ -173,7 +173,7 @@ class Spower(object):
           dev = d
           break
       if dev is None:
-        raise SusbError("USB device(%s) not found" % serialname)
+        raise Exception("Power", "USB device(%s) not found" % serialname)
     else:
       try:
         dev = dev_list[0]