MIPS: Remove "weak" from get_c0_compare_int() declaration

Weak header file declarations are error-prone because they make every
definition weak, and the linker chooses one based on link order (see
10629d711ed7 ("PCI: Remove __weak annotation from pcibios_get_phb_of_node
decl")).

get_c0_compare_int() is defined in several files.  Each definition is weak,
so I assume Kconfig prevents two or more from being included.  The caller
contains default code used when get_c0_compare_int() isn't defined at all.

Add a weak get_c0_compare_int() definition with the default code and remove
the weak annotation from the declaration.

Then the platform implementations will be strong and will override the weak
default.  If multiple platforms are ever configured in, we'll get a link
error instead of calling a random platform's implementation.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10686/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/time.h

@@ -51,7 +51,7 @@ extern int __weak get_c0_perfcount_int(void);
 /*
  * Initialize the calling CPU's compare interrupt as clockevent device
  */
-extern unsigned int __weak get_c0_compare_int(void);
+extern unsigned int get_c0_compare_int(void);
 extern int r4k_clockevent_init(void);
 
 static inline int mips_clockevent_init(void)

arch/mips/kernel/cevt-r4k.c

@@ -174,6 +174,11 @@ int c0_compare_int_usable(void)
 	return 1;
 }
 
+unsigned int __weak get_c0_compare_int(void)
+{
+	return MIPS_CPU_IRQ_BASE + cp0_compare_irq;
+}
+
 int r4k_clockevent_init(void)
 {
 	unsigned int cpu = smp_processor_id();
@@ -189,11 +194,9 @@ int r4k_clockevent_init(void)
 	/*
 	 * With vectored interrupts things are getting platform specific.
 	 * get_c0_compare_int is a hook to allow a platform to return the
-	 * interrupt number of it's liking.
+	 * interrupt number of its liking.
 	 */
-	irq = MIPS_CPU_IRQ_BASE + cp0_compare_irq;
-	if (get_c0_compare_int)
-		irq = get_c0_compare_int();
+	irq = get_c0_compare_int();
 
 	cd = &per_cpu(mips_clockevent_device, cpu);