arm: imx: Default to SYS_THUMB_BUILD for i.MX6/7

In the case of i.MX6 and i.MX7 family SoCs it is safe (from an errata
point of view) to use thumb2 by default to save space.

Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 36c9c2f..0bc4322 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -823,6 +823,7 @@
 	select CPU_V7A
 	select ROM_UNIFIED_SECTIONS
 	imply MXC_GPIO
+	imply SYS_THUMB_BUILD
 
 config ARCH_MX7
 	bool "Freescale MX7"
@@ -833,6 +834,7 @@
 	select SYS_FSL_SEC_COMPAT_4
 	select SYS_FSL_SEC_LE
 	imply MXC_GPIO
+	imply SYS_THUMB_BUILD
 
 config ARCH_MX6
 	bool "Freescale MX6"
@@ -840,8 +842,8 @@
 	select SYS_FSL_HAS_SEC if IMX_HAB
 	select SYS_FSL_SEC_COMPAT_4
 	select SYS_FSL_SEC_LE
-	select SYS_THUMB_BUILD if SPL
 	imply MXC_GPIO
+	imply SYS_THUMB_BUILD
 
 if ARCH_MX6
 config SPL_LDSCRIPT