x86: Fix clflush invocation in flushCacheLine

This fixes flushCacheLine to flush the line pointer to be vaddr,
not the cache line of the stack location holding the vaddr pointer

include/arch/x86/arch/machine/hardware.h

@@ -86,9 +86,9 @@ uint32_t CONST getCacheLineSize(void);
 uint32_t CONST getCacheLineSizeBits(void);
 
 /* Flushes a specific memory range from the CPU cache */
-static inline void flushCacheLine(void* vaddr)
+static inline void flushCacheLine(volatile void* vaddr)
 {
-    asm volatile("clflush %[vaddr]" :: [vaddr] "m"(vaddr));
+    asm volatile ("clflush %[vaddr]" : [vaddr] "+m"(*((volatile char *)vaddr)));
 }
 
 void flushCacheRange(void* vaddr, uint32_t size_bits);