soc/intel/icelake: Increase bootblock size

This patch fixes icelake build brokenness due to bootblock size
issue.

Increase the bootblock size to 48K to match skylake.  With UART
enabled we are very near the 32K limit, and with upcoming changes
to add USB devices in devicetree for a icelake board it is over
the current 32K limit.

BUG=b:122485106
TEST=Able to build dragonegg

Change-Id: I66706e66ac1bce677fe11022d0eef44b9efc2e76
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/30702
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Rizwan Qureshi <rizwan.qureshi@intel.com>
Reviewed-by: Aamir Bohra <aamir.bohra@intel.com>
diff --git a/src/soc/intel/icelake/Kconfig b/src/soc/intel/icelake/Kconfig
index 727fccee..6343ca5 100644
--- a/src/soc/intel/icelake/Kconfig
+++ b/src/soc/intel/icelake/Kconfig
@@ -176,7 +176,7 @@
 
 config C_ENV_BOOTBLOCK_SIZE
 	hex
-	default 0x8000
+	default 0xC000
 
 config CBFS_SIZE
 	hex