ARM: at91: add sam_linux_is_optee_available() function

Add sam_linux_is_optee_available() which allows to know if OP-TEE is
available for Linux. This function is used by code which needs to
know if we running with OP-TEE available or not.
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
[claudiu.beznea: edit commit title and message, renamed
 sam_linux_is_in_normal_world() into sam_linux_is_optee_available()]
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Link: https://lore.kernel.org/r/20220606145701.185552-2-clement.leger@bootlin.com

arch/arm/mach-at91/sam_secure.c

@@ -27,6 +27,12 @@ struct arm_smccc_res sam_smccc_call(u32 fn, u32 arg0, u32 arg1)
 	return res;
 }
 
+bool sam_linux_is_optee_available(void)
+{
+	/* If optee has been detected, then we are running in normal world */
+	return optee_available;
+}
+
 void __init sam_secure_init(void)
 {
 	struct device_node *np;

arch/arm/mach-at91/sam_secure.h

@@ -14,5 +14,6 @@
 
 void __init sam_secure_init(void);
 struct arm_smccc_res sam_smccc_call(u32 fn, u32 arg0, u32 arg1);
+bool sam_linux_is_optee_available(void);
 
 #endif /* SAM_SECURE_H */