dumpstate: don't read /proc/interrupts

/proc/interrupts may be dumped by dumpstate HAL if required.
The framework dependency on this file is unnecessary, since the
interrupt names are hardware / kernel dependent anyway.

Bug: 36486169
Test: 'adb shell bugreport' on sailfish
Change-Id: I336318b24ce4bcc5b710645359b7c4ccda3f6989
Signed-off-by: Sandeep Patil <sspatil@google.com>