plat/marvell: remove subversion from Marvell make files

Subversion is not reflecting the Marvell sources variant anymore.
This patch removes version.mk from Marvell plafroms.
Signed-off-by: Konstantin Porotchkin <kostap@marvell.com>
Change-Id: I8f3afbe3fab3a38da68876f77455f449f5fe0179

plat/marvell/armada/common/marvell_common.mk

@@ -6,10 +6,6 @@
 MARVELL_PLAT_BASE		:= plat/marvell/armada
 MARVELL_PLAT_INCLUDE_BASE	:= include/plat/marvell/armada
 
-include plat/marvell/version.mk
-
-VERSION_STRING			+=(Marvell-${SUBVERSION})
-
 SEPARATE_CODE_AND_RODATA	:= 1
 
 # flag to switch from PLL to ARO

plat/marvell/version.mk

-SUBVERSION = devel-18.12.2