ips: remove pointless #warning

non-x86 builds want the #warning in the IPS code about compiling on the wrong
architecture removed because it keeps triggering on their platforms build
farms.  Transform from a compile time warning into a runtime one with taint to
preserve the original intent of the authors.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>