'linux/compat.h' included in 'process_vm_access.c' is duplicated.

Link: https://lkml.kernel.org/r/20210306132122.220431-1-zhang.yunkai@zte.com.cnSigned-off-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>