Add RLOGx

This will eventually allow us to remove the code in
logd_write.c#__android_log_write which uses the tag
to direct logs to the radio buffer.

Change-Id: Ic992c0b8d1cf000b1814dc7786d2a40becf75eaf
Use Rlog instead of Log

Changing __android_log_write so the tag warns users relying on the
tag to direct log output to the radio buffer to instead use Rlog or RLOG.

Change-Id: I04b7bb5e620c1ab22b9b495382a252b539947e28