arc: remove defaults for NUM_IRQS let SoC set it

Let the SoC decide the number of the IRQs. Fixes a bug where
Quark SE gets the default instead of the declared value in the SoC
Kconfig.

Change-Id: I978c923fbe2a0737ace27ec951bc3a46e8976584
Signed-off-by: Anas Nashif <anas.nashif@intel.com>
1 file changed