tools/include: Sync asm-generic/bitops/fls.h with the kernel sources

To pick up the changes from:

  cb4ede9 ("riscv: Avoid code duplication with generic bitops implementation")

This should address these tools/perf build warnings:

  Warning: Kernel ABI header differences:
    diff -u tools/include/asm-generic/bitops/__fls.h include/asm-generic/bitops/__fls.h
    diff -u tools/include/asm-generic/bitops/fls.h include/asm-generic/bitops/fls.h

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240408185520.1550865-9-namhyung@kernel.org

Author: namhyung

tools/include/asm-generic/bitops/__fls.h

@@ -5,12 +5,12 @@
 #include <asm/types.h>
 
 /**
- * __fls - find last (most-significant) set bit in a long word
+ * generic___fls - find last (most-significant) set bit in a long word
  * @word: the word to search
  *
  * Undefined if no set bit exists, so code should check against 0 first.
  */
-static __always_inline unsigned long __fls(unsigned long word)
+static __always_inline unsigned long generic___fls(unsigned long word)
 {
 	int num = BITS_PER_LONG - 1;
 
@@ -41,4 +41,8 @@ static __always_inline unsigned long __fls(unsigned long word)
 	return num;
 }
 
+#ifndef __HAVE_ARCH___FLS
+#define __fls(word) generic___fls(word)
+#endif
+
 #endif /* _ASM_GENERIC_BITOPS___FLS_H_ */

tools/include/asm-generic/bitops/fls.h

@@ -3,14 +3,14 @@
 #define _ASM_GENERIC_BITOPS_FLS_H_
 
 /**
- * fls - find last (most-significant) bit set
+ * generic_fls - find last (most-significant) bit set
  * @x: the word to search
  *
  * This is defined the same way as ffs.
  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  */
 
-static __always_inline int fls(unsigned int x)
+static __always_inline int generic_fls(unsigned int x)
 {
 	int r = 32;
 
@@ -39,4 +39,8 @@ static __always_inline int fls(unsigned int x)
 	return r;
 }
 
+#ifndef __HAVE_ARCH_FLS
+#define fls(x) generic_fls(x)
+#endif
+
 #endif /* _ASM_GENERIC_BITOPS_FLS_H_ */