riscv: Fix missing __free_pages() in check_vector_unaligned_access()

The locally allocated pages are never freed up, so add the corresponding
__free_pages().

Fixes: e7c9d66 ("RISC-V: Report vector unaligned access speed hwprobe")
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexandre Ghiti <[email protected]>

Author: Alexandre Ghiti

arch/riscv/kernel/unaligned_access_speed.c

@@ -349,7 +349,7 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
 		pr_warn("cpu%d: rdtime lacks granularity needed to measure unaligned vector access speed\n",
 			cpu);
 
-		return;
+		goto free;
 	}
 
 	if (word_cycles < byte_cycles)
@@ -363,6 +363,9 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
 		(speed ==  RISCV_HWPROBE_MISALIGNED_VECTOR_FAST) ? "fast" : "slow");
 
 	per_cpu(vector_misaligned_access, cpu) = speed;
+
+free:
+	__free_pages(page, MISALIGNED_BUFFER_ORDER);
 }
 
 static int riscv_online_cpu_vec(unsigned int cpu)