ARM: OMAP2+: rename gpmc_probe_nor_child() to gpmc_probe_generic_child()

The gpmc_probe_nor_child() function is used in the GPMC driver to
configure the GPMC for a NOR child device node.

But this function is quite generic and all the NOR specific configuration
is made by the driver of the actual NOR flash memory used.

Other Pseudo-SRAM devices such as ethernet controllers need a similar
setup so by making this function generic it can be used for those too.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Jon Hunter <jon-hunter@ti.com>