gen_isr_tables: make vector offset a hidden option

If this is set incorrectly things will break all over the place.
Needs a default defined per-arch and left alone.

Change-Id: I3f8c842937a240297ee21589a22a7a9e51dbdfad
Signed-off-by: Andrew Boie <[email protected]>

Author: Andrew Boie

arch/Kconfig

@@ -153,14 +153,15 @@ config GEN_SW_ISR_TABLE
 
 config GEN_IRQ_START_VECTOR
 	int
-	prompt "Starting vector for user-configurable interrupts"
 	default 0
 	depends on GEN_ISR_TABLES
 	help
 	On some architectures, part of the vector table may be reserved for
 	system exceptions and is declared separately from the tables
 	created by gen_isr_tables.py. When creating these tables, this value
 	will be subtracted from CONFIG_NUM_IRQS to properly size them.
+	This is a hidden option which needs to be set-per architecture and
+	left alone.
 
 source "arch/*/Kconfig"