loader/efi/linux: Print EFI status as hex number instead of uint

loader/efi/linux: Print EFI status as hex number instead of uint

EFI status codes are of different classes depending on the first byte and
all error status codes defined in appendix D of the main spec start from
1 and have the high bit set. When printing as a uint, the decimal is a very
large number that needs have the high bit cleared get the spec error code.
This can be easily visually done by a human if the number is printed as hex.

Signed-off-by: Glenn Washburn <development@efficientek.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>