Previously, sbuffer was only ready when there were empty items.
In a scenario where there are no empty items but requests received from sq can be merged,
sbuffer will refuse to receive requests from sq, which will result in failure to run at full throughput.

If a memset is detected, let each newly allocated sbuffer entry wait for 32 cycles
before writing to the dcache.(When memset and the write bandwidth are full,
at least two sbs are executed in each cycle and 2 bytes are written.
It takes 32 cycles to fill a cacheline)

This will help improve sbuffer utilization

only works in MemSet Pattern