Kernel: Generate page fault events from the kernel profiler

Hook the kernel page fault handler and capture page fault events when
the fault has a current thread attached in TLS. We capture the eip and
ebp so we can unwind the stack and locate which pieces of code are
generating the most page faults.

Co-authored-by: Gunnar Beutner <gbeutner@serenityos.org>

Kernel/UnixTypes.h

@@ -60,6 +60,7 @@ enum {
     PERF_EVENT_CONTEXT_SWITCH = 1024,
     PERF_EVENT_KMALLOC = 2048,
     PERF_EVENT_KFREE = 4096,
+    PERF_EVENT_PAGE_FAULT = 8192,
 };
 
 #define WNOHANG 1