usb: gadget: uvc: clarify comment about string descriptors
usb: gadget: uvc: clarify comment about string descriptors

The comment that describes string descriptors allocation isn't clear,
fix it.

Signed-off-by: Laurent Pinchart <3ded2f39a78f0d7044839546f95841842b4d7c96@ideasonboard.com>
Tested-by: Bhupesh Sharma <4ea540b5fc8347f73706cff6303216b2e0bede0b@st.com>
Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs