ALSA: firewire-lib: change a member of event structure to suppress sparse wanings to bool type

Commit a9c4284b ("ALSA: firewire-lib: add context information to
tracepoints") adds new members to tracepoint events of this module, to
represent context information. One of the members is bool type and
this causes sparse warnings.

16:1: warning: expression using sizeof bool
60:1: warning: expression using sizeof bool
16:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)
60:1: warning: odd constant _Bool cast (ffffffffffffffff becomes 1)

This commit suppresses the warnings, by changing type of the member
to 'unsigned int'. Additionally, this commit applies '!!' idiom to
get 0/1 from 'in_interrupt()'.

Fixes: a9c4284b ("ALSA: firewire-lib: add context information to tracepoints")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>