ALSA: firewire-lib: code refactoring for helper function to compute OHCI 1394 cycle

Some macros and functions are renamed so that they compute isochronous
cycle within maximum count of second in isochronous context of 1394
OHCI.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20210518130048.146596-5-o-takashi@sakamocchi.jp


Signed-off-by: Takashi Iwai <tiwai@suse.de>