Correct SPL uses of MULTIPLEXER

This converts 3 usages of this option to the non-SPL form, since there is
no SPL_MULTIPLEXER defined in Kconfig

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>

drivers/Makefile

@@ -18,7 +18,6 @@ obj-$(CONFIG_$(SPL_TPL_)INPUT) += input/
 obj-$(CONFIG_$(SPL_TPL_)LED) += led/
 obj-$(CONFIG_$(SPL_TPL_)MMC) += mmc/
 obj-y += mtd/
-obj-$(CONFIG_$(SPL_)MULTIPLEXER) += mux/
 obj-$(CONFIG_$(SPL_TPL_)ETH) += net/
 obj-$(CONFIG_$(SPL_TPL_)PCH) += pch/
 obj-$(CONFIG_$(SPL_TPL_)PCI) += pci/
@@ -87,6 +86,7 @@ obj-$(CONFIG_FASTBOOT) += fastboot/
 obj-$(CONFIG_FWU_MDATA) += fwu-mdata/
 obj-y += misc/
 obj-$(CONFIG_MMC) += mmc/
+obj-$(CONFIG_MULTIPLEXER) += mux/
 obj-$(CONFIG_NVME) += nvme/
 obj-$(CONFIG_PCI_ENDPOINT) += pci_endpoint/
 obj-y += dfu/