According to the latest documentation from GOWIN -
"UG285-1.4E Gowin BSRAM & SSRAM User Guide"
The dual port BSRAM of all 55nm devices (including GW1N, GW2A and GW1A
series) does not support the read-before-write mode (WRITE_MODE = 2)
Signed-off-by: YRabbit <rabbit@yrabbit.cyou>