UBI: fix gcc warning
UBI: fix gcc warning

Fix the following warning:

drivers/mtd/ubi/vmt.c: In function 'ubi_rename_volumes':
drivers/mtd/ubi/vmt.c:642: warning: statement with no effect

Signed-off-by: Artem Bityutskiy <19b5733dcea388885746d36043d3568bba5b4df7@nokia.com>

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