ia64: drop unused IA64_FW_EMU ifdef

It's a remnant of deleted hpsim emulation target removed in fc5bad03
("ia64: remove the hpsim platform").

Link: https://lkml.kernel.org/r/20210323224009.240625-1-slyfox@gentoo.org


Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>