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/usbdevice_fs.h b/libc/kernel/uapi/linux/usbdevice_fs.h
index 03f3bfb..7936ad9 100644
--- a/libc/kernel/uapi/linux/usbdevice_fs.h
+++ b/libc/kernel/uapi/linux/usbdevice_fs.h
@@ -110,6 +110,7 @@
 #define USBDEVFS_CAP_MMAP 0x20
 #define USBDEVFS_CAP_DROP_PRIVILEGES 0x40
 #define USBDEVFS_CAP_CONNINFO_EX 0x80
+#define USBDEVFS_CAP_SUSPEND 0x100
 #define USBDEVFS_DISCONNECT_CLAIM_IF_DRIVER 0x01
 #define USBDEVFS_DISCONNECT_CLAIM_EXCEPT_DRIVER 0x02
 struct usbdevfs_disconnect_claim {
@@ -158,4 +159,7 @@
 #define USBDEVFS_DROP_PRIVILEGES _IOW('U', 30, __u32)
 #define USBDEVFS_GET_SPEED _IO('U', 31)
 #define USBDEVFS_CONNINFO_EX(len) _IOC(_IOC_READ, 'U', 32, len)
+#define USBDEVFS_FORBID_SUSPEND _IO('U', 33)
+#define USBDEVFS_ALLOW_SUSPEND _IO('U', 34)
+#define USBDEVFS_WAIT_FOR_RESUME _IO('U', 35)
 #endif