einj_mem_uc: Support before 3.14 kernel

Run einj_mem_uc in 3.10 kernel:
./einj_mem_uc: cannot open '/sys/kernel/debug/apei/einj/flags'

The 'flags' is added by 3482fb5e0c1c (ACPI, APEI, EINJ: Changes to the
ACPI/APEI/EINJ debugfs interface) on 3.14 kernel. Add kernel version
check.

Signed-off-by: Bixuan Cui <cuibixuan@linux.alibaba.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
1 file changed