xilinx: versal: Enable i2c mux uclass with pca954x driver

Xilinx is using pca954x i2c muxes on a lot of boards that's why enable this
driver by default.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/c090aea3436c7a4ebe698da6cbc70e70a14baae3.1659691195.git.michal.simek@amd.com
diff --git a/configs/xilinx_versal_virt_defconfig b/configs/xilinx_versal_virt_defconfig
index 6e61abd..c4d7aac 100644
--- a/configs/xilinx_versal_virt_defconfig
+++ b/configs/xilinx_versal_virt_defconfig
@@ -69,6 +69,8 @@
 CONFIG_FPGA_VERSALPL=y
 CONFIG_DM_I2C=y
 CONFIG_SYS_I2C_CADENCE=y
+CONFIG_I2C_MUX=y
+CONFIG_I2C_MUX_PCA954x=y
 CONFIG_DM_MAILBOX=y
 CONFIG_ZYNQMP_IPI=y
 CONFIG_MISC=y