unicore32-softmmu: Add ps2 support

This patch adds ps2/keyboard support, and enables CONFIG_PCKBD.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/default-configs/unicore32-softmmu.mak b/default-configs/unicore32-softmmu.mak
index 4d4fbfc..de38577 100644
--- a/default-configs/unicore32-softmmu.mak
+++ b/default-configs/unicore32-softmmu.mak
@@ -1,3 +1,4 @@
 # Default configuration for unicore32-softmmu
 CONFIG_PUV3=y
 CONFIG_PTIMER=y
+CONFIG_PCKBD=y