[sparkplug] Remove unused sparkplug_inline_smi flag

Bug: v8:11420
Change-Id: I61182b0b1b3ee8d1ea55df48577077dbd3a36ec5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2695397Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72742}

src/flags/flag-definitions.h

@@ -578,7 +578,6 @@ DEFINE_INT(ticks_scale_factor_for_top_tier, 10,
 // Flags for Sparkplug
 DEFINE_BOOL(sparkplug, false, "enable experimental sparkplug baseline compiler")
 DEFINE_BOOL(always_sparkplug, false, "directly tier up to sparkplug")
-DEFINE_BOOL(sparkplug_inline_smi, true, "inline fast paths for smi ops")
 DEFINE_NEG_IMPLICATION(sparkplug, write_protect_code_memory)
 DEFINE_IMPLICATION(always_sparkplug, sparkplug)