Kernel/riscv64: Make the kernel compilable using GCC

This commit adds all necessary includes, so all functions are properly
declared.
PCI.cpp is moved to PCI/Initializer.cpp, as that matches the header
path.

Kernel/Arch/riscv64/DebugOutput.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/Arch/DebugOutput.h>
 #include <Kernel/Library/Assertions.h>
 
 namespace Kernel {

Kernel/Arch/riscv64/Interrupts.cpp

@@ -7,6 +7,8 @@
 #include <AK/Error.h>
 #include <AK/Types.h>
 
+#include <Kernel/Arch/CPU.h>
+#include <Kernel/Arch/Interrupts.h>
 #include <Kernel/Arch/TrapFrame.h>
 #include <Kernel/Interrupts/GenericInterruptHandler.h>
 

Kernel/Arch/riscv64/PCI/Initializer.cpp

@@ -4,6 +4,7 @@
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
+#include <Kernel/Bus/PCI/Initializer.h>
 #include <Kernel/Library/Assertions.h>
 
 namespace Kernel::PCI {

Kernel/Arch/riscv64/PageDirectory.h

@@ -172,7 +172,7 @@ public:
 
     RISCV64::CSR::SATP satp() const
     {
-        return {
+        return RISCV64::CSR::SATP {
             .PPN = m_directory_table->paddr().get() >> PADDR_PPN_OFFSET,
             .ASID = 0,
             .MODE = RISCV64::CSR::SATP::Mode::Sv39,

Kernel/CMakeLists.txt

@@ -522,7 +522,7 @@ elseif("${SERENITY_ARCH}" STREQUAL "riscv64")
         Arch/riscv64/Interrupts.cpp
         Arch/riscv64/PageDirectory.cpp
         Arch/riscv64/Panic.cpp
-        Arch/riscv64/PCI.cpp
+        Arch/riscv64/PCI/Initializer.cpp
         Arch/riscv64/PowerState.cpp
         Arch/riscv64/pre_init.cpp
         Arch/riscv64/Processor.cpp