[XTENSA] Add .literal sections for various init sectiont to linker script

[XTENSA] Add .literal sections for various init sectiont to linker script

Xtensa requires separate .literal section for each .text section.
Adding addition init sections for cpuinit, meminit, and devinit,
broke the Xtensa linker script, so, add these literal sections
manually for now.

Signed-off-by: Chris Zankel <chris@zankel.net>