Added power pins to the custom memory cells

- connected mem_wb to power (guarded by lvs)
- updated defines.v to use the custom memory
diff --git a/verilog/rtl/defines.v b/verilog/rtl/defines.v
index f5a6c90..8275a11 100644
--- a/verilog/rtl/defines.v
+++ b/verilog/rtl/defines.v
@@ -7,7 +7,7 @@
 
 // Type and size of soc_mem
 // `define USE_OPENRAM
-// `define USE_CUSTOM_DFFRAM
+`define USE_CUSTOM_DFFRAM
 // don't change the following without double checking addr widths
 `define MEM_WORDS 256