net: qrtr: fifo: Add bounds check on tx path

Add bounds check on values read from shared memory in the tx path. In
cases where the VM is misbehaving, the qrtr transport should exit and
print a warning when bogus values may cause out of bounds to be read.

Change-Id: Ic4bdb838ea7f72703327020ec31db2f4150b3474
Signed-off-by: Sarannya S <quic_sarannya@quicinc.com>