imx6: rename Generic profile to Default, fixes u-boot image build issue

u-boot.mk checks for the Default profile to build images for all targets.
This brings the target default profile in sync with other targets

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/imx6/profiles/100-default.mk

@@ -5,13 +5,13 @@
 # See /LICENSE for more information.
 #
 
-define Profile/Generic
+define Profile/Default
   PRIORITY:=1
-  NAME:=Generic (default)
+  NAME:=Default Profile
 endef
 
-define Profile/Generic/Description
+define Profile/Default/Description
  Package set compatible with most Freescale i.MX 6 based boards.
 endef
 
-$(eval $(call Profile,Generic))
+$(eval $(call Profile,Default))