SecurityPkg/RngDxe: Remove ArchGetSupportedRngAlgorithms()

SecurityPkg/RngDxe: Remove ArchGetSupportedRngAlgorithms()

RngGetInfo() is one of the 2 functions of the EFI_RNG_PROTOCOL.
RngGetInfo() is currently a mere wrapper around
ArchGetSupportedRngAlgorithms() which is implemented differently
depending on the architecture used.

RngGetInfo() does nothing more than calling
ArchGetSupportedRngAlgorithms(). So remove it, and let RngGetInfo()
be implemented differently according to the architecture.

This follows the implementation of the other function of the
EFI_RNG_PROTOCOL, RngGetRNG().

Signed-off-by: Pierre Gondois <pierre.gondois@arm.com>
Acked-by: Jiewen Yao <jiewen.yao@intel.com>