sparc: correct section of current_pc()

Latest mainline gives this section mismatch on sparc:

The function current_pc() references
the variable __init no_sun4u_here.
This is often because current_pc lacks a __init
annotation or the annotation of no_sun4u_here is wrong.

Since current_pc() is used only in early time, it is correct to
put it in .init section.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

arch/sparc/kernel/head.S

@@ -465,6 +465,7 @@ gokernel:
 		mov	%o7, %g4		! Save %o7
 
 		/* Jump to it, and pray... */
+		__INIT
 current_pc:
 		call	1f
 		 nop