powerpc/machdep: Remove CONFIG_PPC_HAS_FEATURE_CALLS

Last user was removed by commit 7bbd8277 ("[PATCH] ppc64: very
basic desktop g5 sound support").
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/803779fffb4ee0801746b2173d37cea3b273f821.1630667612.git.christophe.leroy@csgroup.eu

arch/powerpc/include/asm/machdep.h

@@ -10,11 +10,6 @@
 
 #include <asm/setup.h>
 
-/* We export this macro for external modules like Alsa to know if
- * ppc_md.feature_call is implemented or not
- */
-#define CONFIG_PPC_HAS_FEATURE_CALLS
-
 struct pt_regs;
 struct pci_bus;	
 struct device_node;