MIPS: idle: Remove leftover __pastwait symbol and its references

The __pastwait symbol was only used by the address_is_in_r4k_wait_irqoff
function but this is no longer used since the SMTC removal in commit
b633648c5ad3 ('MIPS: MT: Remove SMTC support'). That symbol also led to
build failures under certain random configuration due to the way the
compiler compiled the r4k_wait_irqoff function. If that function was
called multiple times, the __pastwait symbol was redefined breaking the
build like this:

CHK include/generated/compile.h
CC arch/mips/kernel/idle.o
{standard input}: Assembler messages:
{standard input}:527: Error: symbol `__pastwait' is already defined

Link: http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=1244879922.24479.30.camel%40falcon
Signed-off-by: Markos Chandras <[e-mail]>
Cc: [e-mail]
Cc: Markos Chandras <[e-mail]>
Patchwork: https://patchwork.linux-mips.org/patch/7791/
Signed-off-by: Ralf Baechle <[e-mail]>

arch/mips/include/asm/idle.h

···
 extern void r4k_wait(void);
 extern asmlinkage void __r4k_wait(void);
 extern void r4k_wait_irqoff(void);
-extern void __pastwait(void);
 
 static inline int using_rollback_handler(void)
 {
 	return cpu_wait == r4k_wait;
-}
-
-static inline int address_is_in_r4k_wait_irqoff(unsigned long addr)
-{
-	return addr >= (unsigned long)r4k_wait_irqoff &&
-	       addr < (unsigned long)__pastwait;
 }
 
 extern int mips_cpuidle_wait_enter(struct cpuidle_device *dev,

arch/mips/kernel/idle.c

···
 		"	wait			\n"
 		"	.set	pop		\n");
 	local_irq_enable();
-	__asm__(
-	"	.globl __pastwait	\n"
-	"__pastwait:			\n");
 }
 
 /*