riscv: remove irqflags.h inclusion in asm/bitops.h

The arch/riscv/include/asm/bitops.h does not functionally require
including /linux/irqflags.h. Additionally, adding
arch/riscv/include/asm/percpu.h causes a circular inclusion:
kernel/bounds.c
->include/linux/log2.h
->include/linux/bitops.h
->arch/riscv/include/asm/bitops.h
->include/linux/irqflags.h
->include/linux/find.h
->return val ? __ffs(val) : size;
->arch/riscv/include/asm/bitops.h

The compilation log is as follows:
CC kernel/bounds.s
In file included from ./include/linux/bitmap.h:11,
from ./include/linux/cpumask.h:12,
from ./arch/riscv/include/asm/processor.h:55,
from ./arch/riscv/include/asm/thread_info.h:42,
from ./include/linux/thread_info.h:60,
from ./include/asm-generic/preempt.h:5,
from ./arch/riscv/include/generated/asm/preempt.h:1,
from ./include/linux/preempt.h:79,
from ./arch/riscv/include/asm/percpu.h:8,
from ./include/linux/irqflags.h:19,
from ./arch/riscv/include/asm/bitops.h:14,
from ./include/linux/bitops.h:68,
from ./include/linux/log2.h:12,
from kernel/bounds.c:13:
./include/linux/find.h: In function 'find_next_bit':
./include/linux/find.h:66:30: error: implicit declaration of function '__ffs' [-Wimplicit-function-declaration]
66 | return val ? __ffs(val) : size;
| ^~~~~

Signed-off-by: Yunhui Cui <[e-mail]>
Acked-by: Yury Norov (NVIDIA) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paul Walmsley <[e-mail]>

arch/riscv/include/asm/bitops.h

···
 #endif /* _LINUX_BITOPS_H */
 
 #include <linux/compiler.h>
-#include <linux/irqflags.h>
 #include <asm/barrier.h>
 #include <asm/bitsperlong.h>