Update exposed pad design to meet recent KLC.

Created by: krtkr

See https://github.com/KiCad/kicad-footprints/issues/209.

Update exposed pad (EP) design according to new KLC:

• LQFP-144-1EP_20x20mm_P0.5mm_EP4x4mm
• LQFP-144-1EP_20x20mm_P0.5mm_EP5x5mm
• LQFP-144-1EP_20x20mm_P0.5mm_EP6.61x6.61mm
• LQFP-144-1EP_20x20mm_P0.5mm_EP7.2x7.2mm
• LQFP-144-1EP_20x20mm_P0.5mm_EP8.93x8.93mm
• LQFP-32-1EP_5x5mm_P0.5mm
• LQFP-52-1EP_10x10mm_P0.65mm
• LQFP-64-1EP_10x10mm_P0.5mm
• TQFP-44-1EP_10x10mm_P0.8mm
• TQFP-48-1EP_7x7mm_P0.5mm
• TQFP-64-1EP_10x10mm_P0.5mm

A few comments:

• Did not find LQFP-32-1EP at NXP. Found this document https://www.nxp.com/docs/en/brochure/BR1568.pdf. Referred sot401-1 does not have EP, see https://www.nxp.com/docs/en/package-information/SOT401-1.pdf. My guess this package should have 3.45x3.45mm exposed pad.
• For LQFP-52-1EP_10x10mm_P0.65mm_EP4.8x4.8mm found this document https://www.onsemi.com/pub/Collateral/848H-01.PDF, 4.8mm is recommended footprint EP size.
• DId not find referenced '00000049BS.pdf', first googleable document is http://ww1.microchip.com/downloads/en/PackagingSpec/00000049BQ.pdf. No 'TQFP-100-1EP_14x14mm_P0.5mm' and 'TQFP-48-1EP_7x7mm_P0.5mm' at the '00000049BQ.pdf'.
• No documentation for TQFP-64-1EP_10x10mm_P0.5mm.

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