meta-google: remove required npcm8xx-tip-fw version

npcm8xx-tip-fw already specifies per-IGPS_MACHINE configuration in
https://github.com/openbmc/openbmc/blob/4b8284784129e050c556b372e7116f884a168e8c/meta-nuvoton/recipes-bsp/images/npcm8xx-tip-fw_0.5.6.0.4.5.bb#L3

Change-Id: I635dfb6c2ed769d0f098e6ab2443dceaca79b789
Signed-off-by: Anthony <anthonyhkf@google.com>
diff --git a/meta-google/conf/distro/gbmc.conf b/meta-google/conf/distro/gbmc.conf
index 0f2531a..213c7aa 100644
--- a/meta-google/conf/distro/gbmc.conf
+++ b/meta-google/conf/distro/gbmc.conf
@@ -36,4 +36,3 @@
 ERROR_QA:append = " patch-fuzz"
 
 IGPS_MACHINE:npcm8xx = "Google"
-REQUIRED_VERSION_npcm8xx-tip-fw = "0.4.5.0.3.4-GOOGLE2"