Move setexpr to Kconfig

Another shell scripting command that has not been moved.

Moved using tools/moveconfig.py using these settings:

CMD_SETEXPR bool n y

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/configs/Hummingbird_A31_defconfig b/configs/Hummingbird_A31_defconfig
index 015140f..7bc936f 100644
--- a/configs/Hummingbird_A31_defconfig
+++ b/configs/Hummingbird_A31_defconfig
@@ -9,5 +9,6 @@
 CONFIG_DEFAULT_DEVICE_TREE="sun6i-a31-hummingbird"
 CONFIG_SPL=y
 CONFIG_SYS_EXTRA_OPTIONS="USB_EHCI,SUNXI_GMAC,RGMII,MACPWR=SUNXI_GPA(21)"
+CONFIG_CMD_SETEXPR=y
 CONFIG_ETH_DESIGNWARE=y
 CONFIG_AXP221_ALDO1_VOLT=3300