NetworkPkg: Fix an error that the call function declared implicitly.

NetworkPkg: Fix an error that the call function declared implicitly.

Use NetRandomInitSeed() instead of AsmReadTsc() to generate
a random seed.
Macro definition of EFI_HTTP_BOOT_CLIENT_SYSTEM_ARCHITECTURE for EBC architecture.
Add some space to make codes more standard.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Zhang Lubo <lubo.zhang@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: jiaxinwu <jiaxin.wu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17941 6f19259b-4bc3-4df7-8a09-765794883524