ARM: npcm: wpcm450: select interrupt controller driver

The interrupt controller driver is necessary in order to have a
functioning Linux system on WPCM450. Select it in mach-npcm/Kconfig.

Fixes: ece3fe93

 ("ARM: npcm: Introduce Nuvoton WPCM450 SoC")
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210513165627.1767093-1-j.neuschaefer@gmx.net
Link: https://lore.kernel.org/r/20210518071514.604492-1-joel@jms.id.au

'
Signed-off-by: Arnd Bergmann <arnd@arndb.de>