configs/microchip_mpfs_icicle_defconfig: update RVC config option

Update the RISCV_ISA_RVC config option to match updated RISCV kconfig
instruction set options.

Signed-off-by: Jamie Gibbons <jamie.gibbons@microchip.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

configs/microchip_mpfs_icicle_defconfig

@@ -1,6 +1,6 @@
 BR2_riscv=y
 BR2_riscv_g=y
-BR2_RISCV_ISA_CUSTOM_RVC=y
+BR2_RISCV_ISA_RVC=y
 BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_6_1=y
 BR2_TARGET_GENERIC_HOSTNAME="mpfs_icicle"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="board/microchip/mpfs_icicle/post-image.sh"