Enable TUI support for perf in linux-tools

[Herton Ronaldo Krzesinski]

This simple patch series for natty/oneiric/precise adds a build depend
for libnewt-dev, so perf can have its newt interface (TUI) enabled.

SRU Justification
=================

Impact
------
newt UI (TUI) is disabled with perf report if libnewt-dev is unavailable
when perf is built.

Fix
---
Ensure libnewt-dev is installed when building perf, adding the proper
Build-Depends to the linux source.

Testcase
--------
1. perf record <command>
2. perf report --tui
3. perf report --stdio

For 2, newt interface should load with the recorded data (perf.data from
record command). Text interface (--stdio) should continue to work as
before, for the third invocation.