locking/atomic: atomic: remove redundant include

Since commit:

  560cb12a ("locking,arch: Rewrite generic atomic support")

... we conditionally include <linux/irqflags.h> before defining atomics
using locking, and hence do not need to do so unconditionally later in
the header.

This patch removes the redundant include.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210525140232.53872-8-mark.rutland@arm.com

include/asm-generic/atomic.h

@@ -143,8 +143,6 @@ ATOMIC_OP(xor, ^)
 
 #define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
 
-#include <linux/irqflags.h>
-
 static inline void atomic_add(int i, atomic_t *v)
 {
 	atomic_add_return(i, v);