bpftrace/usdt: Use direct loads for case usdt_semaphore_test
bpftrace/usdt: Use direct loads for case usdt_semaphore_test

The value reg in struct pt_regs can be read directly, as it
is a BPF context data. Hence use simple load here.

Suggested-by: Masanori Misono <789bba239773890001881c6e46df0001dd71c086@gmail.com>
Signed-off-by: Sumanth Korikkar <ce55f038c56237666a10109f730271a4db066561@linux.ibm.com>

iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace,iovisor/bpftrace