pflash: Reduce writebuf len for 8-bit flashes.

Flashes connected through an 8 bit bus cannot handle write buffers
larger than 256 bytes.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@petalogix.com>

hw/pflash_cfi01.c

diff --git a/hw/pflash_cfi01.c b/hw/pflash_cfi01.c
index 8f3e567..b0c7b4c 100644
--- a/hw/pflash_cfi01.c
+++ b/hw/pflash_cfi01.c
@@ -599,7 +599,11 @@
     pfl->cfi_table[0x28] = 0x02;
     pfl->cfi_table[0x29] = 0x00;
     /* Max number of bytes in multi-bytes write */
-    pfl->cfi_table[0x2A] = 0x0B;
+    if (width == 1) {
+        pfl->cfi_table[0x2A] = 0x08;
+    } else {
+        pfl->cfi_table[0x2A] = 0x0B;
+    }
     pfl->cfi_table[0x2B] = 0x00;
     /* Number of erase block regions (uniform) */
     pfl->cfi_table[0x2C] = 0x01;