powerpc: Change LOAD_REG_ADDR to use real register names

LOAD_REG_ADDR define is just a wrapper around real instructions so we
can just use real register names here (ie. lower case).
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/opal-wrappers.S

@@ -32,7 +32,7 @@
 	std	r12,PACASAVEDMSR(r13);	\
 	andc	r12,r12,r0;		\
 	mtmsrd	r12,1;			\
-	LOAD_REG_ADDR(R0,.opal_return);	\
+	LOAD_REG_ADDR(r0,.opal_return);	\
 	mtlr	r0;			\
 	li	r0,MSR_DR|MSR_IR;	\
 	andc	r12,r12,r0;		\