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/asm-arm/asm/kvm.h b/libc/kernel/uapi/asm-arm/asm/kvm.h
index 72bcb03..6fdb46c 100644
--- a/libc/kernel/uapi/asm-arm/asm/kvm.h
+++ b/libc/kernel/uapi/asm-arm/asm/kvm.h
@@ -187,8 +187,10 @@
 #define KVM_DEV_ARM_ITS_RESTORE_TABLES 2
 #define KVM_DEV_ARM_VGIC_SAVE_PENDING_TABLES 3
 #define KVM_DEV_ARM_ITS_CTRL_RESET 4
+#define KVM_ARM_IRQ_VCPU2_SHIFT 28
+#define KVM_ARM_IRQ_VCPU2_MASK 0xf
 #define KVM_ARM_IRQ_TYPE_SHIFT 24
-#define KVM_ARM_IRQ_TYPE_MASK 0xff
+#define KVM_ARM_IRQ_TYPE_MASK 0xf
 #define KVM_ARM_IRQ_VCPU_SHIFT 16
 #define KVM_ARM_IRQ_VCPU_MASK 0xff
 #define KVM_ARM_IRQ_NUM_SHIFT 0