UPSTREAM: seqlock: Cure some more scoped_seqlock() optimization fails

Arnd reported an x86 randconfig using gcc-15 tripped over
__scoped_seqlock_bug(). Turns out GCC chose not to inline the
scoped_seqlock helper functions and as such was not able to optimize
properly.

[ mingo: Clang fails the build too in some circumstances. ]

Reported-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: https://patch.msgid.link/20251204104332.GG2528459@noisy.programming.kicks-ass.net
(cherry picked from commit 90dfeef1cd38dff19f8b3a752d13bfd79f0f7694)

Cherry-pick by Gemini, reviewed by me

BUG=b:565345075
TEST=CQ
Branches: N/A

Change-Id: I4867cf571b3bc54bd2070b028df01f66cae4578a
Signed-off-by: George Burgess IV <gbiv@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/8535114
Reviewed-by: Suleiman Souhlal <suleiman@google.com>
Commit-Queue: George Burgess <gbiv@chromium.org>
Tested-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Sean Paul <sean@poorly.run>