Use case insensitive comparison for the machine's architechture

Use case insensitive comparison for the machine's architechture

boot loader specification states:

architecture: refers to the architecture this entry is for. The argument
should be an architecture identifier, using the architecture vocabulary
defined by the EFI specification (i.e. IA32, x64, IA64, ARM, AA64, …).
If specified and it does not match the local system architecture this
entry should be hidden. The comparison should be done case-insensitively.

Example: architecture aa64

https://uapi-group.org/specifications/specs/boot_loader_specification/#type-1-boot-loader-entry-keys
(cherry picked from commit f819a516dbbddb16724f33dcef5badcb6fe8b80b)