riscv: annotate check_unaligned_access_boot_cpu() with __init

This function is solely called as an initcall, thus annotate it with
__init.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Evan Green <evan@rivosinc.com>
Link: https://lore.kernel.org/r/20231004151405.521596-7-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/kernel/cpufeature.c

@@ -645,7 +645,7 @@ out:
 	__free_pages(page, get_order(MISALIGNED_BUFFER_SIZE));
 }
 
-static int check_unaligned_access_boot_cpu(void)
+static int __init check_unaligned_access_boot_cpu(void)
 {
 	check_unaligned_access(0);
 	return 0;