arm: omap3: pm34xx.c: Fix omap3_pm_init() error out paths

It appears that the error paths were overlooked when the
omap3_pm_init() routine had the prcm chain handler code
added.  Fix this by adding a goto target and reordering
the error handling code.  Also fix how the irq argument
for free_irq() is determined.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>