firmware: trusted_foundations: add ARMv7 dependency

The "+sec" extension is invalid for older ARM architectures, but
the code can now be built on any ARM configuration:

/tmp/trusted_foundations-2d0882.s: Assembler messages:
/tmp/trusted_foundations-2d0882.s:194: Error: architectural extension `sec' is not allowed for the current base architecture
/tmp/trusted_foundations-2d0882.s:201: Error: selected processor does not support `smc #0' in ARM mode
/tmp/trusted_foundations-2d0882.s:213: Error: architectural extension `sec' is not allowed for the current base architecture
/tmp/trusted_foundations-2d0882.s:220: Error: selected processor does not support `smc #0' in ARM mode

Add a dependency on ARMv7 for the build.

Fixes: 4cb5d9ec ("firmware: Move Trusted Foundations support")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NOlof Johansson <olof@lixom.net>

drivers/firmware/Kconfig

@@ -256,7 +256,7 @@ config TI_SCI_PROTOCOL
 
 config TRUSTED_FOUNDATIONS
 	bool "Trusted Foundations secure monitor support"
-	depends on ARM
+	depends on ARM && CPU_V7
 	help
 	  Some devices (including most early Tegra-based consumer devices on
 	  the market) are booted with the Trusted Foundations secure monitor