[ARM] add machine-specific hook to machine_kexec

Provide the option to call a machine-specific function
before kexec'ing a new kernel.

Signed-off-by: Eric Cooper <ecc@cmu.edu>
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>

arch/arm/include/asm/kexec.h

@@ -50,6 +50,9 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
 	}
 }
 
+/* Function pointer to optional machine-specific reinitialization */
+extern void (*kexec_reinit)(void);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* CONFIG_KEXEC */