[coreboot] Patch for getpir when using input image file

[Marc Bertens]

Signed-off: Marc Bertens

There was a problem when using the getpir utility with the coreboot_ram
file, basically removed the loop around the search function, in the
coreboot_ram image the start $PIR is not on a 16 byte boundary. due to
the search already was matching 6 bytes of the start of the table
(including the version of the table), this was not necessary any
more.

Marc