x86/kconfig: Disable CONFIG_GENERIC_HWEIGHT and remove __HAVE_ARCH_SW_HWEIGHT

Remove an unnecessary arch complication:

arch/x86/include/asm/arch_hweight.h uses __sw_hweight{32,64} as
alternatives, and they are implemented in arch/x86/lib/hweight.S

x86 does not rely on the generic C implementation lib/hweight.c
at all, so CONFIG_GENERIC_HWEIGHT should be disabled.

__HAVE_ARCH_SW_HWEIGHT is not necessary either.

No change in functionality intended.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Uros Bizjak <ubizjak@gmail.com>
Link: http://lkml.kernel.org/r/1557665521-17570-1-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/Kconfig

@@ -261,9 +261,6 @@ config GENERIC_BUG
 config GENERIC_BUG_RELATIVE_POINTERS
 	bool
 
-config GENERIC_HWEIGHT
-	def_bool y
-
 config ARCH_MAY_HAVE_PC_FDC
 	def_bool y
 	depends on ISA_DMA_API

arch/x86/include/asm/arch_hweight.h

@@ -12,8 +12,6 @@
 #define REG_OUT "a"
 #endif
 
-#define __HAVE_ARCH_SW_HWEIGHT
-
 static __always_inline unsigned int __arch_hweight32(unsigned int w)
 {
 	unsigned int res;

lib/hweight.c

@@ -10,7 +10,6 @@
  * The Hamming Weight of a number is the total number of bits set in it.
  */
 
-#ifndef __HAVE_ARCH_SW_HWEIGHT
 unsigned int __sw_hweight32(unsigned int w)
 {
 #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
@@ -27,7 +26,6 @@ unsigned int __sw_hweight32(unsigned int w)
 #endif
 }
 EXPORT_SYMBOL(__sw_hweight32);
-#endif
 
 unsigned int __sw_hweight16(unsigned int w)
 {
@@ -46,7 +44,6 @@ unsigned int __sw_hweight8(unsigned int w)
 }
 EXPORT_SYMBOL(__sw_hweight8);
 
-#ifndef __HAVE_ARCH_SW_HWEIGHT
 unsigned long __sw_hweight64(__u64 w)
 {
 #if BITS_PER_LONG == 32
@@ -69,4 +66,3 @@ unsigned long __sw_hweight64(__u64 w)
 #endif
 }
 EXPORT_SYMBOL(__sw_hweight64);
-#endif