arm: mark save_boot_params_ret as a function

As no '.type' was set for save_boot_params_ret in start.S, binutils
did not track whether it was emitted as A32 or T32.  By properly
marking save_boot_params_ret as a potential function entry, we can
make sure that the compiler will insert the appropriate instructions
for branching to save_boot_params_ret both for call-sites emitted as
A32 and T32.

Reported-by: Andy Yan <andy.yan@rock-chips.com>
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Tested-by: Andy Yan <andy.yan@rock-chips.com>

arch/arm/cpu/armv7/start.S

@@ -31,6 +31,7 @@
 
 	.globl	reset
 	.globl	save_boot_params_ret
+	.type   save_boot_params_ret,%function
 #ifdef CONFIG_ARMV7_LPAE
 	.global	switch_to_hypervisor_ret
 #endif