ARM: keystone: Update compatible to have SoC specific matches

With future SoCs of keystone2 family, the generic compatible match
may not be sufficient to handle SoC specific handling. So introduce
matches based on SoC compatiblity.
Signed-off-by: NNishanth Menon <nm@ti.com>
Signed-off-by: NSantosh Shilimkar <ssantosh@kernel.org>

arch/arm/mach-keystone/keystone.c

@@ -97,6 +97,9 @@ static long long __init keystone_pv_fixup(void)
 }
 
 static const char *const keystone_match[] __initconst = {
+	"ti,k2hk",
+	"ti,k2e",
+	"ti,k2l",
 	"ti,keystone",
 	NULL,
 };