MIPS: Reorder MIPS_L1_CACHE_SHIFT priorities

Enabling support for more than one BMIPS CPU in the same build may
result in different L1_CACHE_SHIFT values, e.g.

    CPU_BMIPS5000 selects MIPS_L1_CACHE_SHIFT_7
    CPU_BMIPS4380 selects MIPS_L1_CACHE_SHIFT_6
    anything else defaults to MIPS_L1_CACHE_SHIFT_5

Ensure that if more than one MIPS_L1_CACHE_SHIFT_x option is selected,
Kconfig sets CONFIG_MIPS_L1_CACHE_SHIFT to the highest value.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: jaedon.shin@gmail.com
Cc: abrestic@chromium.org
Cc: tglx@linutronix.de
Cc: jason@lakedaemon.net
Cc: jogo@openwrt.org
Cc: arnd@arndb.de
Cc: computersforpeace@gmail.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8847/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -1233,10 +1233,10 @@ config MIPS_L1_CACHE_SHIFT_7
 
 config MIPS_L1_CACHE_SHIFT
 	int
-	default "4" if MIPS_L1_CACHE_SHIFT_4
-	default "5" if MIPS_L1_CACHE_SHIFT_5
-	default "6" if MIPS_L1_CACHE_SHIFT_6
 	default "7" if MIPS_L1_CACHE_SHIFT_7
+	default "6" if MIPS_L1_CACHE_SHIFT_6
+	default "5" if MIPS_L1_CACHE_SHIFT_5
+	default "4" if MIPS_L1_CACHE_SHIFT_4
 	default "5"
 
 config HAVE_STD_PC_SERIAL_PORT