block: Name the RQF flags enum

JIRA: https://issues.redhat.com/browse/RHEL-79409

commit e711252
Author: Breno Leitao <leitao@debian.org>
Date:   Thu Mar 6 08:27:51 2025 -0800

    block: Name the RQF flags enum

    Commit 5f89154 ("block: Use enum to define RQF_x bit
    indexes") converted the RQF flags to an anonymous enum, which was
    a beneficial change. This patch goes one step further by naming the enum
    as "rqf_flags".

    This naming enables exporting these flags to BPF clients, eliminating
    the need to duplicate these flags in BPF code. Instead, BPF clients can
    now access the same kernel-side values through CO:RE (Compile Once, Run
    Everywhere), as shown in this example:

        rqf_stats = bpf_core_enum_value(enum rqf_flags, __RQF_STATS)

    Suggested-by: Yonghong Song <yonghong.song@linux.dev>
    Signed-off-by: Breno Leitao <leitao@debian.org>
    Link: https://lore.kernel.org/r/20250306-rqf_flags-v1-1-bbd64918b406@debian.org
    Signed-off-by: Jens Axboe <axboe@kernel.dk>

Signed-off-by: Ming Lei <ming.lei@redhat.com>

Author: Ming Lei

include/linux/blk-mq.h

@@ -28,7 +28,7 @@ typedef enum rq_end_io_ret (rq_end_io_fn)(struct request *, blk_status_t);
 typedef __u32 __bitwise req_flags_t;
 
 /* Keep rqf_name[] in sync with the definitions below */
-enum {
+enum rqf_flags {
 	/* drive already may have started this one */
 	__RQF_STARTED,
 	/* request for flush sequence */