Update to android-mainline kernel headers v5.4.

Update generate_uapi_headers.sh to checkout the android mainline
kernel. Also, add a small modification to look for the kernel directory
in common not linux-stable.

Remove deprecated android headers from android/uapi/linux. Also,
remove f_accessory.h since it's in the android mainline kernel.

Test: Builds and runs on walleye.
Change-Id: Ia371305e19f56e6bcc2db6d5b4d299819f07ffc6
diff --git a/libc/kernel/uapi/linux/perf_event.h b/libc/kernel/uapi/linux/perf_event.h
index 9048588..229184f 100644
--- a/libc/kernel/uapi/linux/perf_event.h
+++ b/libc/kernel/uapi/linux/perf_event.h
@@ -198,7 +198,7 @@
   };
   __u64 sample_type;
   __u64 read_format;
-  __u64 disabled : 1, inherit : 1, pinned : 1, exclusive : 1, exclude_user : 1, exclude_kernel : 1, exclude_hv : 1, exclude_idle : 1, mmap : 1, comm : 1, freq : 1, inherit_stat : 1, enable_on_exec : 1, task : 1, watermark : 1, precise_ip : 2, mmap_data : 1, sample_id_all : 1, exclude_host : 1, exclude_guest : 1, exclude_callchain_kernel : 1, exclude_callchain_user : 1, mmap2 : 1, comm_exec : 1, use_clockid : 1, context_switch : 1, write_backward : 1, namespaces : 1, ksymbol : 1, bpf_event : 1, __reserved_1 : 33;
+  __u64 disabled : 1, inherit : 1, pinned : 1, exclusive : 1, exclude_user : 1, exclude_kernel : 1, exclude_hv : 1, exclude_idle : 1, mmap : 1, comm : 1, freq : 1, inherit_stat : 1, enable_on_exec : 1, task : 1, watermark : 1, precise_ip : 2, mmap_data : 1, sample_id_all : 1, exclude_host : 1, exclude_guest : 1, exclude_callchain_kernel : 1, exclude_callchain_user : 1, mmap2 : 1, comm_exec : 1, use_clockid : 1, context_switch : 1, write_backward : 1, namespaces : 1, ksymbol : 1, bpf_event : 1, aux_output : 1, __reserved_1 : 32;
   union {
     __u32 wakeup_events;
     __u32 wakeup_watermark;