HV: rename nuc7i7bnh to nuc7i7dnb

NUC7i7BNH is not a board name but a product name of KBL NUC, and it is
outdated to support LOGICAL_PARTITION scenario and HYBRID scenario.

NUC7i7DNH is the product name of KBL NUC that ACRN currently supported,
but its official board name is NUC7i7DNB, so change the folder name from
"nuc7i7bnh" to "nuc7i7dnb" under arch/x86/configs/.

Please refer more details on below documentation:
Intel® NUC Board/Kit NUC7i7DN Technical Product Specification

Tracked-On: #3446

Signed-off-by: Victor Sun <victor.sun@intel.com>
Reviewed-by: Xiangyang Wu <xiangyang.wu@linux.intel.com>

hypervisor/arch/x86/configs/kbl-nuc-i7

@@ -1 +1 @@
-nuc7i7bnh
+nuc7i7dnb

hypervisor/arch/x86/configs/kbl-nuc-i7.config

@@ -1 +1 @@
-nuc7i7bnh.config
+nuc7i7dnb.config

hypervisor/arch/x86/configs/nuc7i7dnb.config

@@ -1,4 +1,4 @@
 # Generated by Kconfiglib (https://github.com/ulfalizer/Kconfiglib)
-CONFIG_BOARD="nuc7i7bnh"
+CONFIG_BOARD="nuc7i7dnb"
 CONFIG_SERIAL_LEGACY=y
 CONFIG_HV_RAM_START=0x60000000