[IA64] address compiler warnings perfmon.c/salinfo.c

perfmon.c has a dubious cast directly from "int" to "void *". Add
an intermediate cast to "long" to keep gcc happy.

salinfo.c uses "down_trylock()" in a highly creative way (explained
in the comments in the file) ... but it does kick out this warning:

 arch/ia64/kernel/salinfo.c:195: warning: ignoring return value of 'down_trylock'

which people occasionally try to "fix" in ways that do not work. Use some
casts to keep gcc quiet.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>