clk: at91: clk-master: add 5th divisor for mck master

clk-master can have 5 divisors with a field width of 3 bits
on some products.

Change the mask and number of divisors accordingly.

Reported-by: Mihai Sain <mihai.sain@microchip.com>
Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
diff --git a/drivers/clk/at91/pmc.h b/drivers/clk/at91/pmc.h
index a6a714f..f07f535 100644
--- a/drivers/clk/at91/pmc.h
+++ b/drivers/clk/at91/pmc.h
@@ -30,7 +30,7 @@
 
 struct clk_master_characteristics {
 	struct clk_range output;
-	u32 divisors[4];
+	u32 divisors[5];
 	u8 have_div3_pres;
 };