KVM: ia64: 'struct fdesc' build fix

Commit 4611a77 ("[IA64] fix compile failure with non modular builds")
introduced struct fdesc into asm/elf.h, which duplicates KVM's definition.
Remove the latter to avoid the build error.

Signed-off-by: Jes Sorensen <jes@sgi.com>
Acked-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>