soc: ti: pm33xx: Fix some resource leak in the error handling paths of the probe function

'am33xx_pm_rtc_setup()' allocates some resources that must be freed on the
error. Commit 2152fbbd ("soc: ti: pm33xx: Simplify RTC usage to prepare
to drop platform data") has introduced the use of these resources but has
only updated the remove function.

Fix the error handling path of the probe function now.

Fixes: 2152fbbd ("soc: ti: pm33xx: Simplify RTC usage to prepare to drop platform data")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>