Update p10 Rainier config and OCC version handling

- Update p10 Rainier config to remove unneeded options, clarify
  existing settings
- Update occ-p10 package to modernize version handling

 Signed-off-by: Nick Bofferding <bofferdn@us.ibm.com>
diff --git a/openpower/package/occ-p10/occ-p10.mk b/openpower/package/occ-p10/occ-p10.mk
index 14410df..e69ff2e 100644
--- a/openpower/package/occ-p10/occ-p10.mk
+++ b/openpower/package/occ-p10/occ-p10.mk
@@ -4,7 +4,7 @@
 #
 ################################################################################
 
-OCC_P10_VERSION ?= 36b56e72c2dd6c2a2fb21667c55a594f86f6132e
+OCC_P10_VERSION = $(call qstrip,$(BR2_OCC_P10_VERSION))
 # TODO: WORKAROUND: Need to reenable next line and comment out the two lines
 # after that, when code is propagated to a public repo
 #OCC_P10_SITE ?= $(call github,open-power,occ,$(OCC_P10_VERSION))
@@ -23,12 +23,12 @@
 OCC_P10_IMAGE_BIN_PATH = obj/image.bin
 
 OCC_P10_DEPENDENCIES = host-binutils host-ppe42-gcc
-ifeq ($(BR2_OCC_GPU_BIN_BUILD),y)
+ifeq ($(BR2_OCC_P10_GPU_BIN_BUILD),y)
 	OCC_P10_DEPENDENCIES += hostboot-binaries
 endif
 
 define OCC_P10_BUILD_CMDS
-	if [ "$(BR2_OCC_GPU_BIN_BUILD)" == "y"  ]; then \
+	if [ "$(BR2_OCC_P10_GPU_BIN_BUILD)" == "y"  ]; then \
 	    cd $(@D)/src && \
             make PPE_TOOL_PATH=$(PPE42_GCC_BIN) OCC_OP_BUILD=1 CROSS_PREFIX=$(TARGET_CROSS) LD_LIBRARY_PATH=$(HOST_DIR)/usr/lib GPE1_BIN_IMAGE_PATH=$(STAGING_DIR)/hostboot_binaries/ OPOCC_GPU_SUPPORT=1 all; \
 	else \
@@ -41,7 +41,7 @@
 
 define OCC_P10_INSTALL_IMAGES_CMDS
        mkdir -p $(STAGING_DIR)/occ
-       cp $(@D)/$(OCC_P10_IMAGE_BIN_PATH) $(OCC_P10_STAGING_DIR)/$(BR2_OCC_BIN_FILENAME)
+       cp $(@D)/$(OCC_P10_IMAGE_BIN_PATH) $(OCC_P10_STAGING_DIR)/$(BR2_OCC_P10_BIN_FILENAME)
 endef
 
 $(eval $(generic-package))