MSR and syscall changes

- Moved MSR code to separate files with an enum class
- Implemented syscall_enable in C++ using new MSR calls

src/kernel/io.h

@@ -14,16 +14,6 @@ uint8_t inb(uint16_t port);
 /// \arg val   The byte to write
 void outb(uint16_t port, uint8_t val);
 
-/// Read the value of a MSR
-/// \arg addr   The MSR address
-/// \returns    The current value of the MSR
-uint64_t rdmsr(uint64_t addr);
-
-/// Write to a MSR
-/// \arg addr   The MSR address
-/// \arg value  The value to write
-void wrmsr(uint64_t addr, uint64_t value);
-
 /// Pause briefly by doing IO to port 0x80
 /// \arg times  Number of times to delay by writing
 void io_wait(unsigned times = 1);