lib.sh: fix debugfs fw_path in get_ldc_subdir() and missing sudo

One more fix for commit 992efad ("case-lib: lib.sh: use debugfs for
fw_path when available"). There are so many fallbacks in the code that
these ones were kept hidden for long time.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

Author: marc-hb

case-lib/lib.sh

@@ -309,11 +309,11 @@ get_ldc_subdir()
 {
     local subdir='intel/sof' # default
     local fw_path
-    local fw_path_info='/sys/kernel/debug/sof/fw_path'
+    local fw_path_info='/sys/kernel/debug/sof/fw_profile/fw_path'
 
     # either $fw_path_info exists, OR we redefine $fw_path_info with
     # the backwards-compatible alternative based on kernel parameter
-    test -e $fw_path_info ||
+    sudo test -e $fw_path_info ||
 	fw_path_info='/sys/module/snd_sof_pci/parameters/fw_path'
 
     if fw_path=$(sudo cat $fw_path_info); then