cmake: linker: Removed unnecessary regexp in link generator

In the linker script generator there was one error checking
construct that used regexp and that ended up in the generated
linker file, which caused parsing problems with the IAR
linker. It was unnecessary. Also updated
common-rom-kernel-devices.ld.

Signed-off-by: Lars-Ove Karlsson <lars-ove.karlsson@iar.com>