common: Drop linux/bitops.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index 1cebb03..5804aa8 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -10,6 +10,7 @@
 #include <log.h>
 #include <asm/encoding.h>
 #include <dm/uclass-internal.h>
+#include <linux/bitops.h>
 
 /*
  * The variables here must be stored in the data section since they are used