connectx4: Set debug = false

Complete debug messages have become a little overwhelming now that we
are allocating thousands of pages of memory for the adapter. Just for
the moment disabling the hexdumps is the more sensible default.

More fine-grained debug logging is likely needed.

src/apps/mellanox/connectx4.lua

@@ -67,7 +67,7 @@ local cast = ffi.cast
 local band, bor, shl, shr, bswap, bnot =
    bit.band, bit.bor, bit.lshift, bit.rshift, bit.bswap, bit.bnot
 
-local debug = true
+local debug = false
 
 ConnectX4 = {}
 ConnectX4.__index = ConnectX4