arch/x86/acpigen: Implement acpigen functions to return integer & string

Add ACPI method to return integer & string.

Change-Id: I2a668ccadecb71b71531e2eb53a52015fca96738
Signed-off-by: Naresh G Solanki <naresh.solanki@intel.com>
Reviewed-on: https://review.coreboot.org/17450
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/arch/x86/acpigen.c

@@ -1168,6 +1168,18 @@ void acpigen_write_return_byte(uint8_t arg)
 	acpigen_write_byte(arg);
 }
 
+void acpigen_write_return_integer(uint64_t arg)
+{
+	acpigen_emit_byte(RETURN_OP);
+	acpigen_write_integer(arg);
+}
+
+void acpigen_write_return_string(const char *arg)
+{
+	acpigen_emit_byte(RETURN_OP);
+	acpigen_write_string(arg);
+}
+
 /*
  * Generate ACPI AML code for _DSM method.
  * This function takes as input uuid for the device, set of callbacks and

src/arch/x86/include/arch/acpigen.h

@@ -144,6 +144,8 @@ struct opregion {
 	unsigned long regionlen;
 };
 
+void acpigen_write_return_integer(uint64_t arg);
+void acpigen_write_return_string(const char *arg);
 void acpigen_write_len_f(void);
 void acpigen_pop_len(void);
 void acpigen_set_current(char *curr);