sched/smt: Always inline sched_smt_active()

sched_smt_active() can be called from noinstr code, so it should always
be inlined.  The CONFIG_SCHED_SMT version already has __always_inline.
Do the same for its !CONFIG_SCHED_SMT counterpart.

Fixes the following warning:

  vmlinux.o: error: objtool: intel_idle_ibrs+0x13: call to sched_smt_active() leaves .noinstr.text section

Fixes: 321a874 ("sched/smt: Expose sched_smt_present static key")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/1d03907b0a247cf7fb5c1d518de378864f603060.1743481539.git.jpoimboe@kernel.org
Closes: https://lore.kernel.org/r/202503311434.lyw2Tveh-lkp@intel.com/

Author: jpoimboe

include/linux/sched/smt.h

@@ -12,7 +12,7 @@ static __always_inline bool sched_smt_active(void)
 	return static_branch_likely(&sched_smt_present);
 }
 #else
-static inline bool sched_smt_active(void) { return false; }
+static __always_inline bool sched_smt_active(void) { return false; }
 #endif
 
 void arch_smt_update(void);