memory: omap-gpmc: Fix -Wunused-function warnings

memory: omap-gpmc: Fix -Wunused-function warnings

If CONFIG_OF is not set, make W=1 warns:

  drivers/memory/omap-gpmc.c:987:12: warning: ‘gpmc_cs_remap’ defined but not used [-Wunused-function]
  drivers/memory/omap-gpmc.c:926:20: warning: ‘gpmc_cs_get_name’ defined but not used [-Wunused-function]
  drivers/memory/omap-gpmc.c:919:13: warning: ‘gpmc_cs_set_name’ defined but not used [-Wunused-function]

Move them to #ifdef CONFIG_OF block to fix this.

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Roger Quadros <rogerq@ti.com>
Link: https://lore.kernel.org/r/20200901112832.3084-1-yuehaibing%40huawei.com
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>