irq plugin: Parse interrupt counters as unsigned long long.

irq plugin: Parse interrupt counters as unsigned long long.

Hello,

attached patch fixes accounting of most frequent interrupts (like NICs
on routers). E.g. in my case:

213:      76266      76357      76250      76397 2408617852 2411844062 2411642538 2411814531   PCI-MSI-edge      eth1
214: 2621368360 2621463385 2621343444 2621386931    2349184         28         35         32   PCI-MSI-edge      eth0

Here LONG_MAX (2147483647L) overflows in 10 days uptime and strtol()
returns the same value.

As all the values (including counter_t) are unsigned long long int, the
fix is trivial (for now there's no need to check for irq_value overflow;>).

--
Tomasz Pala <gotar@pld-linux.org>

Signed-off-by: Florian Forster <octo@leeloo.lan.home.verplant.org>