blockconsole: use CON_ALLDATA

blockconsole: use CON_ALLDATA

Blockconsole should really see every message ever printed.  The
alternative is to try debugging with information like this:
[166135.633974] Stack:
[166135.634016] Call Trace:
[166135.634029]  <IRQ>
[166135.634156]  <EOI>
[166135.634177] Code: 00 00 55 48 89 e5 0f 1f 44 00 00 ff 15 31 49 80 00 c9 c3 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 0f 1f 44 00 00
[166135.634384]  48 8b 14 25 98 24 01 00 48 8d 14 92 48 8d 04 bd 00 00 00 00

Signed-off-by: Joern Engel <joern@logfs.org>