mtd: nand: pxa3xx_nand: Remove redundant of_match_ptr

The data structure of_match_ptr() protects is always compiled in.
Hence of_match_ptr() is not needed.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>