spi: Migrate CONFIG_LPC32XX_SSP to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
diff --git a/configs/work_92105_defconfig b/configs/work_92105_defconfig
index fb287bd..2451b56 100644
--- a/configs/work_92105_defconfig
+++ b/configs/work_92105_defconfig
@@ -37,3 +37,4 @@
 CONFIG_PHYLIB=y
 CONFIG_DM_SERIAL=y
 CONFIG_SYS_NS16550=y
+CONFIG_LPC32XX_SSP=y