radio: remove access to proc label

Added appropriate access to proc_cmdline.

Bug: 65643247
Test: make/receive phone calls
Test: send/receive text messages
Test: browse internet on LTE network
No denials to 'proc' label are observed during tests.

Change-Id: I59710c75dbb1cf9aec7c2de4c0372d3ab372a31e
diff --git a/sepolicy/vendor/radio.te b/sepolicy/vendor/radio.te
index 83fcbae..47e7d8b 100644
--- a/sepolicy/vendor/radio.te
+++ b/sepolicy/vendor/radio.te
@@ -26,4 +26,4 @@
 binder_call(radio, hal_imsrtp)
 
 # read /proc/cmdline
-allow radio proc:file r_file_perms;
+allow radio proc_cmdline:file r_file_perms;