bancha: correct ROM size to be 48K

Bypass-Presubmit-Reason: tested as part of topic.

Change-Id: I603ec0b2887b5c940bb0e45ac62e7ae95d4655ed
diff --git a/platforms/bancha.repl b/platforms/bancha.repl
index 9e9ece6..7850f9d 100644
--- a/platforms/bancha.repl
+++ b/platforms/bancha.repl
@@ -51,7 +51,7 @@
 // ROM               [‘h0000_8000 - ‘h0000_FFFF)  32KB ROM for Security core secure boot code storage
 // XXX temporarily bump to 48K for bloat/hacks
 rom: Memory.MappedMemory @ sysbus 0x00008000
-    size: 0x0000b000
+    size: 0x0000c000
 
 // eFLASH            [‘h2000_0000 - ‘h200F_FFFF)  1MB eFlash for Security Core
 eflash: Memory.MappedMemory @ sysbus 0x20000000