Kernel: Add better support for bootloaders loading the kernel

Before I assumed that bootloaders loaded the kernel at physical address
0, but this patch kinda allows loading to different addresses. This
still doesn't fully work as kernel bootstrap paging relies on kernel
being loaded at 0

kernel/kernel/Memory/Heap.cpp

@@ -40,8 +40,8 @@ namespace Kernel
 				continue;
 
 			paddr_t start = entry.address;
-			if (start < V2P(g_kernel_end))
-				start = V2P(g_kernel_end);
+			if (start < (vaddr_t)g_kernel_end - KERNEL_OFFSET + g_boot_info.kernel_paddr)
+				start = (vaddr_t)g_kernel_end - KERNEL_OFFSET + g_boot_info.kernel_paddr;
 			if (auto rem = start % PAGE_SIZE)
 				start += PAGE_SIZE - rem;
 

kernel/kernel/Memory/kmalloc.cpp

@@ -1,9 +1,8 @@
 #include <BAN/Errors.h>
 #include <kernel/kprint.h>
+#include <kernel/BootInfo.h>
 #include <kernel/Memory/kmalloc.h>
 
-#include <kernel/Thread.h>
-
 #define MB (1 << 20)
 
 extern uint8_t g_kernel_end[];
@@ -424,7 +423,7 @@ BAN::Optional<Kernel::paddr_t> kmalloc_paddr_of(Kernel::vaddr_t vaddr)
 	using namespace Kernel;
 
 	if ((vaddr_t)s_kmalloc_storage <= vaddr && vaddr < (vaddr_t)s_kmalloc_storage + sizeof(s_kmalloc_storage))
-		return V2P(vaddr);
+		return vaddr - KERNEL_OFFSET + g_boot_info.kernel_paddr;
 
 	return {};
 }