aspeed: g5: eval: drop unused variables

Leave KMACHINE at the OE-core default.  It is only used by the
kernel-yocto bitbake class when dealing with kernel source trees like
the Yocto kernel fork that include KERNEL_FEATURES metadata right in the
source tree.  None of the Aspeed trees do that.

Don't set FLASH_SIZE.  It isn't an OE-core variable and it isn't used
anywhere.

Change-Id: I83dbb8416414e06e998358e19787c69290737f38
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/conf/machine/evb-ast2500.conf b/conf/machine/evb-ast2500.conf
index 81365d4..2689d37 100644
--- a/conf/machine/evb-ast2500.conf
+++ b/conf/machine/evb-ast2500.conf
@@ -1,8 +1,4 @@
-KMACHINE = "aspeed"
-KERNEL_DEVICETREE = "${KMACHINE}-ast2500-evb.dtb"
-
+KERNEL_DEVICETREE = "aspeed-ast2500-evb.dtb"
 UBOOT_MACHINE = "ast_g5_phy_config"
 
-FLASH_SIZE = "32768"
-
 require conf/machine/include/ast2500.inc