perf/x86/intel: Fix and clean up intel_pmu_drain_arch_pebs() type use

The following commit introduced a build failure on x86-32:

  21954c8a0ff ("perf/x86/intel: Process arch-PEBS records or record fragments")

  ...

  arch/x86/events/intel/ds.c:2983:24: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]

The forced type conversion to 'u64' and 'void *' are not 32-bit clean,
but they are also entirely unnecessary: ->pebs_vaddr is 'void *' already,
and integer-compatible pointer arithmetics will work just fine on it.

Fix & simplify the code.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: d21954c ("perf/x86/intel: Process arch-PEBS records or record fragments")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Link: https://patch.msgid.link/20251029102136.61364-10-dapeng1.mi@linux.intel.com

Author: ingomolnar

arch/x86/events/intel/ds.c

@@ -2979,8 +2979,7 @@ static void intel_pmu_drain_arch_pebs(struct pt_regs *iregs,
 	}
 
 	base = cpuc->pebs_vaddr;
-	top = (void *)((u64)cpuc->pebs_vaddr +
-		       (index.wr << ARCH_PEBS_INDEX_WR_SHIFT));
+	top = cpuc->pebs_vaddr + (index.wr << ARCH_PEBS_INDEX_WR_SHIFT);
 
 	index.wr = 0;
 	index.full = 0;