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/mx6qsabresd_defconfig b/configs/mx6qsabresd_defconfig
index 821c251..f39e260 100644
--- a/configs/mx6qsabresd_defconfig
+++ b/configs/mx6qsabresd_defconfig
@@ -1,3 +1,4 @@
 CONFIG_ARM=y
 CONFIG_TARGET_MX6SABRESD=y
 CONFIG_SYS_EXTRA_OPTIONS="IMX_CONFIG=board/freescale/mx6sabresd/mx6q_4x_mt41j128.cfg,MX6Q"
+CONFIG_CMD_SETEXPR=y