ARM: davinci: remove checks for CONFIG_USB_MUSB_PERIPHERAL

The Kconfig symbol USB_MUSB_PERIPHERAL was removed in v3.1. The last two
checks for its macro now always evaluate to false. So remove these
checks.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
[nsekhar@ti.com: also cleaned-up usage in defconfig file]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>