x86/cpu: Add model number for Intel Clearwater Forest processor

Server product based on the Atom Darkmont core.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240117191844.56180-1-tony.luck@intel.com

arch/x86/include/asm/intel-family.h

@@ -162,6 +162,8 @@
 #define INTEL_FAM6_ATOM_CRESTMONT_X	0xAF /* Sierra Forest */
 #define INTEL_FAM6_ATOM_CRESTMONT	0xB6 /* Grand Ridge */
 
+#define INTEL_FAM6_ATOM_DARKMONT_X	0xDD /* Clearwater Forest */
+
 /* Xeon Phi */
 
 #define INTEL_FAM6_XEON_PHI_KNL		0x57 /* Knights Landing */