usb: musb: omap2430: kill redundant assignments in omap2430_probe()

Commit 00a0b1d58af873d842580dcac55f3b156c3a4077 (usb: musb: omap: Add device
tree support for omap musb glue) added assignments of the 'ret' variable to
-ENOMEM on *some* error paths of the calls to devm_kzalloc(), while that
variable was already pre-initialized for to that value, so these assignments
were completely redundant. Kill them, fixing overindented string, while at it.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>