arch/powerpc: Simplify some calculations using ARRAY_SIZE() macro.

Replace a number of array length calculations with the ARRAY_SIZE()
macro, for clarity.

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: York Sun <york.sun@nxp.com>
diff --git a/arch/powerpc/cpu/ppc4xx/reginfo.c b/arch/powerpc/cpu/ppc4xx/reginfo.c
index 339d38a..a42327e 100644
--- a/arch/powerpc/cpu/ppc4xx/reginfo.c
+++ b/arch/powerpc/cpu/ppc4xx/reginfo.c
@@ -321,7 +321,7 @@
 	PRINT_DCR(OPB2PLB40_BCTRL);
 	PRINT_DCR(P4P3BO0_CFG);
 #endif
-	n = sizeof(ppc4xx_reg) / sizeof(ppc4xx_reg[0]);
+	n = ARRAY_SIZE(ppc4xx_reg);
 	for (i = 0; i < n; i++) {
 		value = 0;
 		type = ppc4xx_reg[i].type;