uboot-imx

spl: dm: Kconfig: fix help text for SPL/TPL confusion

TPL_NAND_SUPPORT, TPL_SERIAL_SUPPORT, TPL_SPI_FLASH_SUPPORT and
TPL_SPI_SUPPORT refer to SPL in their help text.  This fixes up
the description to correctly reference TPL.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>