lmb: Switch to generic arch_lmb_reserve_generic()

Switch arc/arm/m68k/microblaze/mips/ppc arch_lmb_reserve() to
arch_lmb_reserve_generic().

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Alexey Brodkin <alexey.brodkin@synopsys.com>
Cc: Angelo Dureghello <angelo@sysam.it>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: Hai Pham <hai.pham.ud@renesas.com>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
Cc: Tom Rini <trini@konsulko.com>
Cc: Wolfgang Denk <wd@denx.de>