EFI: Make our haiku_loader architecture agnostic

* This is the bulk of the work. Anything else should be
  minor cleanups and tweaking.
* riscv64 isn't a viable EFI platform yet.. just acting
  as a stand-in to test a non-x86 EFI haiku_loader

Change-Id: Ib03de81e2b562e693987b86d7b4318209fb1c792
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2256
Reviewed-by: Alex von Gluck IV <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>

headers/private/kernel/boot/platform/efi/arch_mmu.h

@@ -1,12 +0,0 @@
-/*
- * Copyright 2013-2019 Haiku, Inc. All rights reserved.
- * Distributed under the terms of the MIT License.
- */
-#ifndef KERNEL_BOOT_PLATFORM_EFI_ARCH_MMU_H
-#define KERNEL_BOOT_PLATFORM_EFI_ARCH_MMU_H
-
-
-void arch_mmu_init();
-
-
-#endif /* KERNEL_BOOT_PLATFORM_EFI_ARCH_MMU_H */

headers/private/kernel/boot/platform/efi/arch_start.h

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2019-2020, Haiku, Inc. All rights reserved.
+ * Released under the terms of the MIT License.
+ */
+#ifndef __ARCH_START_H
+#define __ARCH_START_H
+
+
+void arch_start_kernel(addr_t kernelEntry);
+
+
+#endif /* __ARCH_START_H */