Kernel: Add KERNEL_MAPPING_BASE to Sections.h and use it in Prekernel

Author: https://github.com/FireFox317
Commit: 33581d5c44
Pull-request: https://github.com/SerenityOS/serenity/pull/16884
Reviewed-by: https://github.com/48cf
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/mrkct
Reviewed-by: https://github.com/nico ✅

Kernel/Prekernel/init.cpp

@@ -90,7 +90,7 @@ extern "C" [[noreturn]] void init()
     __builtin_memcpy(kernel_program_headers, kernel_image + kernel_elf_header.e_phoff, sizeof(ElfW(Phdr)) * kernel_elf_header.e_phnum);
 
     FlatPtr kernel_physical_base = 0x200000;
-    FlatPtr default_kernel_load_base = 0x2000200000;
+    FlatPtr default_kernel_load_base = KERNEL_MAPPING_BASE + 0x200000;
 
     FlatPtr kernel_load_base = default_kernel_load_base;