ARM: OMAP2+: Convert TUSB to use gpmc_cs_program_settings()

Convert the OMAP2+ TUSB code to use the gpmc_cs_program_settings()
function for configuring the various GPMC options instead of directly
programming the CONFIG1 register.

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>