rtc: brcmstb-waketimer: non-functional code changes

rtc: brcmstb-waketimer: non-functional code changes

These changes are not intended to affect functionality, but
simplify the source code. They are performed here to simplify
review and reduce confusion with other changes in this set.

Since set_alarm includes the alarm_irq_enable functionality call
it directly from that function for simplicity (even though it
does nothing at the moment). The order of the declarations is
changed to prevent the need for a prototype.

The function device_init_wakeup() is used to replace the
functions device_set_wakeup_capable() and device_wakeup_enable()
since it is equivalent.

Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230120190147.718976-3-opendmb@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>