Replace the `--loop_max_part` flag with a hardcoded constant.

This flag isn't valuable to configure.

Bug: 162866386
Test: m -j && launch_cvd --daemon
Change-Id: Ifc64597bf86f426df929a31d67201fe59ae509bb
diff --git a/shared/BoardConfig.mk b/shared/BoardConfig.mk
index c990c84..0f7ac32 100644
--- a/shared/BoardConfig.mk
+++ b/shared/BoardConfig.mk
@@ -182,6 +182,8 @@
 BOARD_KERNEL_CMDLINE += init=/init
 BOARD_KERNEL_CMDLINE += androidboot.hardware=cutf_cvm
 
+BOARD_KERNEL_CMDLINE += loop.max_part=7
+
 ifeq ($(TARGET_USERDATAIMAGE_FILE_SYSTEM_TYPE),f2fs)
 BOARD_KERNEL_CMDLINE += androidboot.fstab_suffix=f2fs
 endif