device: a10 -> A10 for consistency

Makefile

@@ -70,7 +70,7 @@ ARCH?=		${_ARCH}
 KERNEL?=	SMP
 QUICK?=		#yes
 ADDITIONS?=	os-dyndns${SUFFIX}
-DEVICE?=	a10
+DEVICE?=	A10
 SPEED?=		115200
 UEFI?=		yes
 GITBASE?=	https://github.com/opnsense

README.md

@@ -54,7 +54,7 @@ Available build options are:
 
 * ADDITIONS:	a list of packages/plugins to add to images
 * ARCH:		the target architecture if not native
-* DEVICE:	loads device-specific modifications, e.g. "a10" (default)
+* DEVICE:	loads device-specific modifications, e.g. "A10" (default)
 * FLAVOUR:	"OpenSSL" (default), "LibreSSL", "Base"
 * KERNEL:	the kernel config to use, e.g. SMP (default)
 * MIRRORS:	a list of mirrors to prefetch sets from

device/A10.conf

@@ -6,4 +6,5 @@ serial_hook()
 	# the sake of demonstration, we keep this little stub.  :)
 }
 
+# unset this for generic device handling, i.e. no device suffix
 unset PRODUCT_DEVICE