xtensa: clean up default platform functions

Drop _F macro used to define default platform functions and rewrite
definitions as normal functions. Don't define separate __platform_*
function and platform_* weak alias, just define a weak function.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

arch/xtensa/kernel/platform.c

@@ -17,23 +17,28 @@
 #include <asm/platform.h>
 #include <asm/timex.h>
 
-#define _F(r,f,a,b)							\
-	r __platform_##f a b;                                   	\
-	r platform_##f a __attribute__((weak, alias("__platform_"#f)))
-
 /*
  * Default functions that are used if no platform specific function is defined.
- * (Please, refer to include/asm-xtensa/platform.h for more information)
+ * (Please, refer to arch/xtensa/include/asm/platform.h for more information)
  */
 
-_F(void, init, (bp_tag_t *first), { });
-_F(void, setup, (char** cmd), { });
-_F(void, idle, (void), { __asm__ __volatile__ ("waiti 0" ::: "memory"); });
+void __weak __init platform_init(bp_tag_t *first)
+{
+}
+
+void __weak __init platform_setup(char **cmd)
+{
+}
+
+void __weak platform_idle(void)
+{
+	__asm__ __volatile__ ("waiti 0" ::: "memory");
+}
 
 #ifdef CONFIG_XTENSA_CALIBRATE_CCOUNT
-_F(void, calibrate_ccount, (void),
+void __weak platform_calibrate_ccount(void)
 {
 	pr_err("ERROR: Cannot calibrate cpu frequency! Assuming 10MHz.\n");
 	ccount_freq = 10 * 1000000UL;
-});
+}
 #endif