linuxkpi: io.h: Only exclude armv6 and armv7 for asm/set_memory.h

Other arches like powerpc* needs it.

Fixes: d387a1b4b1996 ("linuxkpi: io.h: Do not include asm/set_memory.h for armv6 and armv7")
Fixes: 789dbdbb48574 ("linuxkpi: Add arch_io_{reserve,free}_memtype_wc")
Sponsored by: Beckhoff Automation GmbH & Co. KG