Use memset() in CGDCalloc() again

The bug was libfxcg's sys_calloc() using a memsetZero() function which
simply doesn't work properly.

README

@@ -21,6 +21,7 @@ The differences are (I might push it later):
 * Syscall 0x1B0B, getSecondaryVramAddress() is added in libfxcg/
 * abort() is removed from libc/ (CGDOOM has its own)
 * calloc() defined in libc/ (just a call to sys_calloc)
+* sys_calloc() fixed in libfxcg/ to use memset (memsetZero is broken)
 * Linker script outputs in elf32-sh format
 * Linker script sets 500k of RAM instead of 64k
 * LTO disabled (hopefully it could be reenabled later)

cgdoom/cgdoom.c

@@ -20,9 +20,7 @@ void * CGDCalloc(int iSize)
 	void *p = CGDMalloc(iSize);
 	if(p != NULL)
 	{
-		/* volatile here prevents GCC from calling memset(), which
-		   doesn't seem to work for some obscure reason... */
-		for(int i = 0; i < iSize; i++) ((volatile char *)p)[i] = 0;
+		memset(p,0,iSize);
 	}
 	return p;
 }