Convert CONFIG_SYS_MAXARGS to Kconfig

This converts the following to Kconfig:
   CONFIG_SYS_MAXARGS

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/configs/khadas-vim3_android_ab_defconfig b/configs/khadas-vim3_android_ab_defconfig
index df97c51..08f41f3 100644
--- a/configs/khadas-vim3_android_ab_defconfig
+++ b/configs/khadas-vim3_android_ab_defconfig
@@ -19,6 +19,7 @@
 CONFIG_MISC_INIT_R=y
 CONFIG_AVB_VERIFY=y
 CONFIG_ANDROID_AB=y
+CONFIG_SYS_MAXARGS=32
 # CONFIG_CMD_BDI is not set
 CONFIG_CMD_ADTIMG=y
 CONFIG_CMD_ABOOTIMG=y