MIPS: IP28: Select correct L1_CACHE_SHIFT

IP28 has 128 byte cache lines.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7548/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -546,6 +546,7 @@ config SGI_IP28
 	# select SYS_HAS_EARLY_PRINTK
 	select SYS_SUPPORTS_64BIT_KERNEL
 	select SYS_SUPPORTS_BIG_ENDIAN
+	select MIPS_L1_CACHE_SHIFT_7
       help
         This is the SGI Indigo2 with R10000 processor.  To compile a Linux
         kernel that runs on these, say Y here.